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pharmacy期刊最新论文

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pharmacy期刊最新论文

这个是不一定的,文章要写的好,然后就是文章是要符合期刊的要求

开源期刊读者看文章不需要缴费,便于文章传播,可以增加文章的下载量,引用量。我实验室有人曾经在Pharmacology & Pharmacy上发表了一篇文章,本来实验过程并不复杂,实验结果也米有多大的创新点,但是发布以后引用量竟然还不错,这就是开源期刊的优势吧

这个杂志权威挺高的,不过审核稿件很慢的,有的时候不通过不会告知作者,你得一直等下去。我在6月的时候发到中国实用医药一篇文章,现在已经拿到杂志了,当时是通过edu7k @ 发的,还是很靠谱的,要不你问问他们现在还征不征稿件,现在都快到年底了,大部分的刊物都快截稿了,如果需要发的话必须尽快了,我估计你现在开始准备的话,得到明年才能拿到刊物了

开源期刊改变了传统期刊出版的模式,传统期刊很多是作者发表文章不付费,但是作者在完成这个文章的时候他要去购买许多别的文章,开源期刊在发表文章时会收取作者一定的文章处理费,依靠这些费用,出版商能够不依靠政府支持而自给自足;同时由于传播范围广,开源期刊使得文章的受众大大增加,文章的影响力也会随之大增,这一点是传统期刊所不能企及的,从某种程度上来讲,开源期刊实现了传统期刊的转型升级。

期刊最新论文

《计算机工程与应用》。该期刊的主办单位是华北计算技术研究所,每半个月出版一次,为电子信息科学综合核心期刊。创刊时间为1964年,出版地是北京。

谷歌学术是一个可以免费搜索外文学术文章的搜索引擎,包括了世界上绝大部分出版的学术期刊,谷歌学术可了解有关某一领域的学术文献;了解某一作者的著述,并提供书目信息(引用时必需的图书出版信息或期刊论文的刊名、刊期信息)。部分文献可直接下载。

Elsevier(sciencedirect)是荷兰一家全球著名的学术期刊出版商,每年出版大量的学术图书和期刊,大部分期刊被SCI、SSCI、EI收录,是世界上公认的高品位学术期刊。

Web of Science是获取全球学术信息的重要数据库,它收录了全球13000多种权威的、高影响力的学术期刊,内容涵盖自然科学、工程技术、生物医学、社会科学、艺术与人文等领域。Web of Science 包括著名的三大引文索引数据库(SCI、SSCI、A&HCI)。

Wiley Online Library为全学科期刊全文数据库,出版物涵盖学科范围广泛——包括化学、物理学、工程学、农学、兽医学、食品科学、医学、护理学、口腔医学、生命科学、心理学、商业、经济学、社会科学、艺术、人类学等多个学科大约1600多种期刊,以及很多其它重要的跨学科领域的期刊。

SpringerLink是全球最大的在线科学、技术和医学(STM)领域学术资源平台。Springer 的电子图书数据库包括各种的Springer图书产品,如专著、教科书、手册、地图集、参考工具书、丛书等。具体学科涉及:数学、物理与天文学、化学、生命科学、医学、工程学、计算机科学、环境科学、地球科学、经济学、法律。

ProQuest商业信息、学术研究、应用科技数据库涉及商业管理、社会与人文科学、科学与技术、金融与税务、医药学等广泛领域。提供期刊、报纸、参考书、参考文献、书目、索引、地图集、绝版书籍、记录档案、博士论文和学者论文集等各种类型的信息服务,其中ProQuest Dissertations & Theses Global(PQDT Global)是目前世界上规模最大、使用最广泛的博硕士论文数据库。

PubMed 是一个免费的搜寻引擎,提供生物医学方面的论文搜寻以及摘要的数据库。它的数据库来源为MEDLINE。其核心主题为医学,但亦包括其他与医学相关的领域,像是护理学或者其他健康学科。提供指向全文提供者(付费或免费)的链接。

EI在全球的学术界、工程界、信息界中享有盛誉,是科技界共同认可的重要检索工具。涉及领域:机械工程、机电工程、船舶工程、制造技术、矿业、冶金、材料工程、金属材料、有色金属、陶瓷、塑料及聚合物工程等。

IEEE(Institute of Electrical & ElectronicsEngineers)是电气电子工程师协会IEEE和国际工程技术协会IET的全文库。IEEE致力于电气、电子、计算机工程和与科学有关的领域的开发和研究,在太空、计算机、电信、生物医学、电力及消费性电子产品等领域已制定了1300多个行业标准,现已发展成为具有较大影响力的国际学术组织。

百度学术于2014年6月上线,是百度旗下的免费学术资源搜索平台,提供海量中英文文献学术资源,涵盖各类学术期刊、学位、会议论文,部分文献可直接下载。

sci-hub专门免费下载外文文献,但网站经常换域名,有时不稳定,新域名也有卡顿打不开现象,而且没有收录新文献,目前2022年文献基本下不到。

学术文献下载器(),把海量中外文献数据库资源整合一起,涵盖上面提到的文献数据库,文献资源庞大涉及全科,包括谷歌学术和sci-hub下载不了的文献。适合学校资源不够的高校生或者是单位没有数据库资源的科研人员查阅下载文献资料。

小木虫论坛-SCI期刊点评专栏:拥有来自国内各大院校、科研院所的博硕士研究生和企业研发人员对期刊的专业点评,覆盖了8000+ SCI期刊杂志的专业点评信息,为国内外学术科研人员论文投稿、期刊选择等提供了专业的建议。小木虫论坛秉承“为中国学术科研免费提供动力”宗旨,已成为千万硕博 ...浏览6707 回答81 Epigenetics经验分享:with editor一个月了,好慢呐,有战友投过这个期刊 么,版面费多少? 2 0 2021-07-01 ms8933482113232354 影响因子: 经验分享:EPIGENETICS-US的2020年度#影响因子#为 168 0 2021-02-18 ms6032332839474392 …浏览6707 回答81 科技大数据知识发现平台平台围绕大数据与文献情报智能服务,提供知识发现丰富化和多维度化:提供多维度分面展示,快速发现知识;利用STKOS语义支持相关搜索词分析与规范;提供对专利的关联发现,辅助了解当前关注方向的专利产出,辅助寻求科研合作关系;提供对期刊的关联发现,对期刊按领域、研究方向、期刊的 ...浏览6707 回答81 Editorial:BrainInsulinResistanceinNeurodevelopmental首页 资讯 期刊 导师 问答 求职 发Paper 文献直达 高级搜索 期刊列表 论文助手 搜索 当前位置: X-MOL 学术 › Front. Neurosci. › 论文详情 Editorial: Brain Insulin Resistance in …如何快速使用endnote首先推荐你一个网站,xmol。. 为了搜索你的领域,首先要了解两个方法,第一doi,第二,关键词。. 后者你需要科学上网 。. 你看到了一篇文献,你可以在文献里找到doi或者是以文章期刊名,页码等的引用格式。. 复制doi或者引用格式到xmol,一搜就会直达文章 ...科研过程中,如何订阅本领域重要的期刊,使其整期推送新的 ...2019-7-30如何评价化学咨询平台x-mol? - 知乎2016-4-11你写论文时发现了哪些非常神的网站? - 知乎2016-2-27查看更多结果如何快速查询JACS文献XMOL化学 2015-08-11 2698人看过 JACS可以说是每个化学人梦寐以求的能发一篇论文的地方,可以说是化学类杂志的龙头。化学人经常需要查询JACS的文献。如何在谷歌学术不能用、ACS访问太慢、百度太渣的情况下,快速查询到JACS的文献呢?AnalyticalandBioanalyticalChemistry期刊最新论文,化学Analytical and Bioanalytical Chemistry期刊最新论文,,顶级期刊最新论文图文内容,出版社网站每日同步更新,点击标题直达论文原文,自定义关注的期刊,覆盖PubMed的论文库,快速方便精准的找到您想要的 …iomedicalMicrodevices期刊最新论文,化学/材料,Biomedical Microdevices期刊最新论文,,顶级期刊最新论文图文内容,出版社网站每日同步更新,点击标题直达论文原文,自定义关注的期刊,覆盖PubMed的论文库,快速方便精准的找到您想要的论文中国实用外科杂志中国实用外科杂志Chinese Journal of Practical Surgery. 核心期刊 JST Pж (AJ) CSCD 统计源期刊. 基本信息. 曾用刊名: 实用外科杂志. 主办单位: 中国医师协会;中国实用医学杂志社. 出版周期: 月刊. ISSN: 1005-2208. CN: …化学SCI期刊目录导航SCI期刊搜索 - 最新影响因子查询 中科院分区源于2019年12月17日《2019年中国科学院文献情报中心期刊分区表》“基础版”,仅供参考! 仪器仪表 光谱学 全科医学与补充医学 分析化学 化学综合 声学 学科教育 工程:化工 工程:土木 应用化学 数学跨学科应用 无机 ...小木虫论坛-SCI期刊点评专栏:拥有来自国内各大院校、科研院所的博硕士研究生和企业研发人员对期刊的专业点评,覆盖了8000+ SCI期刊杂志的专业点评信息,为国内外学术科研人员论文投稿、期刊选择等提供了专业的建议。小木虫论坛秉承“为中国学术科研免费提供动力”宗旨,已成为千万硕博 ...Epigenetics经验分享:with editor一个月了,好慢呐,有战友投过这个期刊 么,版面费多少? 2 0 2021-07-01 ms8933482113232354 影响因子: 经验分享:EPIGENETICS-US的2020年度#影响因子#为 168 0 2021-02-18 ms6032332839474392 …科技大数据知识发现平台平台围绕大数据与文献情报智能服务,提供知识发现丰富化和多维度化:提供多维度分面展示,快速发现知识;利用STKOS语义支持相关搜索词分析与规范;提供对专利的关联发现,辅助了解当前关注方向的专利产出,辅助寻求科研合作关系;提供对期刊的关联发现,对期刊按领域、研究方向、期刊的 ...Editorial:BrainInsulinResistanceinNeurodevelopmental首页 资讯 期刊 导师 问答 求职 发Paper 文献直达 高级搜索 期刊列表 论文助手 搜索 当前位置: X-MOL 学术 › Front. Neurosci. › 论文详情 Editorial: Brain Insulin Resistance in …如何快速使用endnote首先推荐你一个网站,xmol。. 为了搜索你的领域,首先要了解两个方法,第一doi,第二,关键词。. 后者你需要科学上网 。. 你看到了一篇文献,你可以在文献里找到doi或者是以文章期刊名,页码等的引用格式。. 复制doi或者引用格式到xmol,一搜就会直达文章 ...科研过程中,如何订阅本领域重要的期刊,使其整期推送新的 ...2019-7-30如何评价化学咨询平台x-mol? - 知乎2016-4-11你写论文时发现了哪些非常神的网站? -如何快速查询JACS文献XMOL化学 2015-08-11 2698人看过 JACS可以说是每个化学人梦寐以求的能发一篇论文的地方,可以说是化学类杂志的龙头。化学人经常需要查询JACS的文献。如何在谷歌学术不能用、ACS访问太慢、百度太渣的情况下,快速查询到JACS的文献呢?AnalyticalandBioanalyticalChemistry期刊最新论文,化学Analytical and Bioanalytical Chemistry期刊最新论文,,顶级期刊最新论文图文内容,出版社网站每日同步更新,点击标题直达论文原文,自定义关注的期刊,覆盖PubMed的论文库,快速方便精准的找到您想要的 …BiomedicalMicrodevices期刊最新论文,化学/材料,Biomedical Microdevices期刊最新论文,,顶级期刊最新论文图文内容,出版社网站每日同步更新,点击标题直达论文原文,自定义关注的期刊,覆盖PubMed的论文库,快速方便精准的找到您想要的论文

sci期刊最新一期

第一种:web of sciencesci收录的期刊,可以在web of science网站上查询到。当查看某一本sci的期刊号时,就可以登录web of science,按照提示,完成该本sci期刊的检索,在相关信息介绍中,就可以找到sci期刊号。

第二种:中国知网中国知网是非常大的数据库,收录了很多期刊。我们可以登录中国知网,检索要查询的sci期刊,只要该本sci期刊收录,就可以找到该本期刊的介绍,查看到对应的期刊号。

第三种:sci期刊分区名单sci期刊名单每年都会更新一次,每次更新都会公布最新的期刊分区名单。这份名单中,包括每本sci期刊的介绍,自然也可以查看到对应的期刊号。

一区sci期刊有哪些如下:

一区sci期刊有Nature和Science,一区sci期刊还有Cell Metabolism 、Cancer Cell、Science Advances、Cell Reports、Nature Microbiology、Nature Biotechnology、Autophagy、Journal of Hepatology、Hepatology、Circulation等刊物,这些刊物在本专业中都是顶尖刊物,发表难度也是可想而知的。

国内也有很多优秀刊物被检索收录,这部分刊物也是国内作者发表sci论文选择刊物时首先会关注并选择的,包括Cell Research、Mol Cell、Cell Discovery、Fungal Diversity、Molecular Plant、Protein & Cell、Cellular & Molecular Immunology、Bone Research等等。

一区二区是sci期刊特有的期刊分类标准,sci将其检索的期刊按照影响因子高低分为四个区,也就是一区二区三区四区,四个区中对应不同的刊物,四个区中一区影响因子最高,四区最低,所以一区二区论文对应的就是发表在一区期刊和二区期刊的论文。

中文sci期刊如下:化学学报、物理学报、高等学校化学学报、岩石学报、植物分类学报、物理化学学报、高分子学报、分析化学、地球物理学报、无机化学学报、有机化学、无机材料学报、生物化学与生物物理进展、化学进展、稀有金属材料与工程、光谱学与光谱分析、新型碳材料、金属学报、红外与毫米波学报。

SCI全称是ScienceCitationIndex,是美国科学信息研究院(InstituteforScientificInformation,简称ISI)出版的一部世界著名的期刊文献检索工具,其出版形式包括印刷版期刊和光盘版及联机数据库,还发行了互联网上Web版数据库。SCI收录全世界出版的数、理、化、农、林、医、生命科学、天文、地理、环境、材料、工程技术等自然科学各学科的核心期刊约3500种。

sci经过50多年的发展,现在已经发展成为当代世界非常重要的大型数据库,并且已经列入国际六大著名检索系统之一。这是一部非常重要的检索工具书,同时也是科学研究成果评价的一项重要依据。

被SCI收录的中国期刊,整体数量还是比较少的,但是依然是一个缓慢的上升趋势。想查找这个还是比较容易的,大家直接进入知网就可以查询到。先点击期刊导航,然后点击数据库刊源导航,再点击SCI科学引文索引。所有被收录的中国期刊就能在这里查到了。

films期刊最新论文

1. ,T.,. Direct Determination of the Island Size Distribution for Parallelogram—Shaped Islands.《Application of Surface Science》,1982,11~12,634~. ,T.—,,An Alternative Approach to the Quantitative Determination of Grain Size Distribution in X-Ray Diffraction.《Acta Crystallographica》,1982,A38⑹,800~. 赵立华,冯克安,伍乃娟。W(112)P(2 1)—O化学吸附系统有序—无序相变的重整化群理论分析。《物理学报》,1986,35⑴,104~. Zhao Lihua,Luo Enzhou,Wu Naijuan,Feng Kean. Quantitative Evaluation of Island Separation and Island Size Distribution in Chemisorption.《Chinese Physics Letters》,1987,4⑾,509~. 赵立华,冯克安,伍乃娟。表面化学吸附层的结构相变。《物理》,1988,17⑸,261~. ,,. Effects of Nearest and Next—Nearest Neighbour Interaction Parameters on Atomic Correlation Functions of Stepped Surfaces. 《Applied Physics A》,1990,50⑶,595~. Zhao Lihua,Wu Lijun,Huang Qizhong,Yang Qiaoqin. TEM Study of C—B4C—SiC Composites with Silicon Additive.《Journal of Materials Science Letters》,1996,15⑵,353~. ,,,. Direct Observation of Incommensurate Modulation in Phase—Separeted Cu—Rich .《Physical Review Letters》,1998,80⑿,2701~. ,,,,. In Situ Observation of the Ferroelectric—Paraelectric Phase Transition in a Triglycine Sulfate Crystal.《Physical Review B》,2000,61⑴,203~. Wu Lijun,Zhao Lihua,Hu Wangyu,Wang Lingling,Xiao Jueming. A TEM Study on the Crystallization of Amporphous Fe73Si3B24 Alloys.《Physica B》,1994,193⑴,116~. Wang Lingling,Zhao Lihua,Hu Wangyu,Wu Lijun,Zhang Bangwei. Effect of Composition on Physical Properties of Amorphous Fe-Si-B Alloys.《Trans. Nonferrous Met. Soc. China》,1997,7⑵,155~159. SCI、EI收录。12. Wang Lingling,Zhao Lihua,Zhang Bangwei,Liao Shuzhi,Ouyang Yifang,Hu Wangyu. On Structure and Crystallization of Amorphous Fe-Mo-W-B Alloys Obtained by Electroess Plating.《Z. Metallkd.》,1997,88⑿,945~948. SCI,EI收录。1998年湖南省自然科学优秀学术论文一等奖。13. Hu Wanagyu,Zhao Lihua,Yang Qiaoqin,Wang Lingling,Zhang Bangwei. Crystallization Behavior of Amorphous Alloys.《Trans. Nonferrous Met. Soc. China》,1998,8⑴,64~68. SCI、EI收录。14. Wang Lingling,Zhao Lihua,Hu Wangyu,Wu Lijun,Zhang Bangwei. Curie Temperature of Amorphous Fe-Si-B and Fe-W-Si-B Alloys.《RARE METALS》,1998,17⑵,81~87. EI收录。15. 王玲玲,赵立华,张邦维,胡望宇,舒小林,欧阳义芳,廖树帜。化学镀Fe-Mo-W-B非晶态合金的晶化。《稀有金属材料与工程》,1998,27⑸,282~285. SCI收录。16. Wang Lingling,Zhao Lihua,Zhang Bangwei,Ouyang Yifang,Liao Shuzhi,Hu Wangyu. Composition Dependence of Some Physical Properties of Fe-TM-B(TM=Mo,W,Mo-W) Alloys Obtained by Electroless Plating.《Plat. Surf. Fin.》,1998,85⑿,96~98. SCI收录。17. 王玲玲,赵立华,张邦维,胡望宇,舒小林,盛 霞。化学镀Fe-TM-B(TM=Sn,W,Mo-W)合金的磁性研究。《稀有金属材料与工程》,1999,28⑴,46~49. SCI收录。18. Wang Lingling,Zhao Lihua,Zhang Bangwei,Hu Wangyu,Shu Xiaolin,Sheng Xia. Magnetic Properties of Fe-TM-B(TM=Sn,W,Mo-W) Alloys Prepared by Electroless Plating.《Z. Metallkd.》,1999,90⑸,338~341. EI收录。19. Wang Lingling,Zhao Lihua,Zhang Bangwei,Hu Wangyu,Shu Xiaolin,Sheng Xia,Fang Zhiyuan. Crystallization study of electroless Fe-Sn-B amorphous alloy deposits.《J. Alloys Compd.》,1999,287,234~238. SCI、EI收录。20. 王玲玲,赵立华,胡望宇,张邦维,舒小林,袁晓俭,盛 霞,廖 蔚。化学镀Fe-Al-P初探。《湖南大学学报》,1999,26⑵,12~. 王玲玲,赵立华,张邦维,胡望宇,舒小林,盛 霞,温雪梅。非晶态Fe-Sn-B合金化学镀层的制备及耐蚀性研究。《功能材料》,1999,30⑶,285~. Wang Lingling,Zhao Lihua,Hu Wangyu,Shu Xiaolin,Yuan Xiaojian,Zhang Bangwei. Primary Study for the Technology of Electroless Plating Fe-Al-P Alloys.《Acta Metallurgica Sinica》(English Letters). 1999,12⑸,722~735. EI收录。23. Wang Lingling,Zhao Lihua,Zhang Bangwei,Liao Shuzhi,Ouyang Yifang,Hu Wangyu,Shu Xiaolin,Yuan Xiaojian. Annealing Temperature Dependence of A-C Magnetic Losses and Microhardness in Fe-TM-B(TM=Fe,Mo,W,Mo-W) Alloys Obtained by Electroless Plating.《Plat. Surf. Fin.》,1999,86⑿,84~87. SCI收录。24. Wang Lingling,Zhao Lihua,Huang Guifang,Yuan Xiaojian,Zhang Bangwei,Zhang Jianyong. Composition,structure and corrosion characteristics of Ni-Fe-P and Ni-Fe-P-B alloy deposits prepared by electroless plating.《Surf. Coat. Tech.》,2000,126⑶,272~278. SCI、EI收录。2002年湖南省自然科学优秀学术论文二等奖。25. Wang Lingling,Zhao Lihua,Ouyang Yifang,Liao Shuzhi,Zhang Bangwei. Electroless Deposition of Fe-Mo-W-B Amorphous Alloys.《Rare Metals》,2002,19⑷,265~268. SCI、EI收录。26. Wang Lingling,Zhao Lihua,Huang Guifang,Yuan Xiaojian,Zhang Bangwei. Crystallization of Ni-Fe-P Amorphous Films Prepared by Electroless Plating.《Procedings of SPIE》,2000,,473~476. ISTP收录。27. Wang Lingling,Zhao Lihua,Hu Wangyu,Shu Xiaolin,Zhang Bangwei. Corrosion,Microhardness and wettablity of electroless Fe-Sn-B Alloy Films.《Adv. Mat. Eng. Tech.》,2001,2(SPM1),635~640. SCI、EI收录。28. 王玲玲,赵立华,黄桂芳,袁晓俭,张邦维,张建勇。化学镀Ni-Fe-P及Ni-Fe-P-B合金膜的磁性。《材料导报》,2001,15⑶,65~. Wang Lingling,Zhao Lihua,Huang Guifang,Yuan Xiaojian,Hu Wangyu,Shu Xiaolin,Zhang Bangwei,Zhang Jianyong. The Structure & Microhardness of Ni-Fe-P & Ni-Fe-P-B Alloy Deposits Prepared by Electroless Plating.《Plat. Surf. Finsh.》,2001,88⑹,92~95. SCI收录。2002年湖南省自然科学优秀学术论文二等奖。30. Wang Lingling,Zhao Lihua,Huang Guifang,Yuan Xiaojian,Zhang Bangwei. The Structure and Crystallization of Amorphous Ni-Fe-P-B Alloys Prepared by Electroless Plating.《Z. Metallkd.》,2001,92⑷,391~395. SCI、EI收录。31. Wang Lingling,Zhao Lihua,Hu Wangyu,Zhang Bangwei,Shu Xiaolin,Sheng Xia. Chemical Iron-Tin-Boron Films.《Metal Finish.》,2001,99⑹,92~. 黄维清,王玲玲,邓辉球,胡望宇,赵立华。机械合金化法制备Al-Cu-Fe纳米非晶合金。《中国有色金属学报》,200 1,11⑷,646~. 王玲玲,赵立华,黄维清,黄桂芳,张建勇。化学沉积Ni-Fe-P-B合金膜的结构和显微硬度,《湖南大学学报》,2001,28⑹,42~. 邓辉球,胡望宇,舒小林,赵立华,张邦维,Monte Carlo simulation of the surface segregation of Pt-Pd and Pt-Ir alloys with an analytic embedded-atom method,Surface Science,517 (2002)177-185. SCI,EI收录.35. 邓辉球,胡望宇,舒小林,赵立华,张邦维,用分析型嵌入原子方法计算Pd-Au合金的热力学性质,计算物理,19⑸(2002). 邓辉球,胡望宇,舒小林,赵立华,张邦维,Pt-Rh二元合金系表面偏聚的分析型EAM模型计算,金属学报,37⑸(2001)467-471. SCI收录.37. 邓辉球,胡望宇,舒小林,赵立华,张邦维,Monte Carlo simulation of the surface segregation on PdPt alloy with an analytic EAM potential,Mechanics and Material Engineering for Science and Experiments,Editors: Yichun Zhou,Yuanxian Gu,Zheng Li,Science Press New York Ltd.,2001,p359-362. ISTP收录.38. 邓辉球,赵立华,黄维清,胡望宇,王玲玲,准晶薄膜与涂层的制备、性能与应用,功能材料,32⑵(2001). 邓辉球,胡望宇,舒小林,赵立华,张邦维,Cu-Ni二元合金系表面聚集的Monte Carlo模拟计算,材料科学与工艺,9 (2001) . 邓辉球,赵立华,掺氟提高YBaCuO高温超导体超导特性的机理研究,功能材料,32(2001)788 790

李霞.顾幸勇.刘琪 查看详情 [期刊论文] -中国陶瓷2004(03) 高朋召 三维碳纤维预制体/陶瓷基复合材料的制备及性能研究 2004 廖树帜.张邦维 查看详情 [期刊论文] -稀有金属材料与工程1998(05) 郑燕青.施尔畏.李汶军 查看详情 [期刊论文] -中国科学2001(04) 葛荣德.刘志宏 查看详情 1995 Voleeanov E 查看详情 2007(2-3) Blumm J 查看详情 2005(09) 更多...相似文献(10条)期刊论文 Sol-gel法制备ZrO2/钙铝硅系微晶玻璃复合材料的研究 - 中国陶瓷2005,41(1) 期刊论文 Sol-Gel法制备Al2O3-SiO2-TiO2-ZrO2复合陶瓷膜的研究 - 中国陶瓷2003,39(6) 外文期刊 Synthesis of ZrO2-SiO2 mesocomposite with high ZrO2 content via a novel sol-gel method 2005,84(1/3) 外文期刊 Optical properties of sol-gel derived ZrO2-TiO2 composite films 2007,515(20/21) 期刊论文 溶胶-凝胶法制备定向排列的纳米结构二氧化锆薄膜 - 清华大学学报(自然科学版)2001,41(4_5) 外文期刊 Influence of La2O3 and ZrO2 as promoters on surface and catalytic properties of CuO/MgO system prepared by sol-gel method 2006,299(0) 外文期刊 Photocatalytic degradation of 2,4-dichlorophenoxiacetic acid and 2,4,6-trichlorophenol with ZrO2 and Mn/ZrO2 sol-gel materials 2006,37(3) 期刊论文 Sol-Gel法制备ZrO2粉的析晶机制 - 稀有金属材料与工程2005,34(z1) 外文会议 Preparation of ZrO2/nano-TiO2 composite powder by sol-gel method 2007 外文期刊 Phase evolution of sol-gel CaO-ZrO2 using sulfuric acid as hydrolysis catalyst 2006,37(3

在国内外学术期刊发表的主要论文如下:1. Nd-Fe-B (B≤50at.%)三元系相图的研究,《中国科学》A辑,, , 1985, . Phase Diagrams of Nd-Fe-B Ternary System, <>, , , 1986, . 混合自旋 (S=1,1/2)模型具有再次近邻反铁磁相互作用晶格基态,《物理学报》, , 1988, 17074. Ising 自旋 (s=1/2)反铁磁超晶格低温热力学,《低温物理学报》 , , 1989, . Ising 自旋 (s=1) 周期超晶格反铁磁基态,《低温物理学报》 , , 1989, . Thermodynamics at low temperature of Ising antiferromagnetic superlattices, Chinese Physics (USA), , , 1990, . Temperature dependence of magnetization and paramagnetism of ferromagnetic- antiferromagnetic superlattices, J. Phys. Condens. Matters, , , 1990, . Properties of a superlattice composed of identical ferromagnetic films with antiferromagnetic interfacial coupling, J. Phys. Condens. Matters, , , 1991, . Temperature and field dependence of magnetization of superlattices with antiferromagnetic coupling, Phys. Lett. A, , , 1991, . Magnetic properties of a transverse Ising film with s=1/2, J. Phys. Condens. Matters, , , 1992, . Temperature dependence of magnetic susceptibility of antiferromagnetic superlattice, Phys. Lett. A, , 1992, . Magnetic properties of antiferromagnetic superlattices, J. Phys. Condens. Matters, , , 1993, . Phase diagrams of transverse Ising film, Physica A, , , 1993, . Magnetisation and susceptibilities of diluted Ising thin magnetic film in a transverse field, Physica A, , , 1996, . Reflection and transmission by magnetic multilayers, J. Magn. Magn. Materials, , , 2000, . Transmission by antiferromagnetic-nonmagnetic multilayers, J. Phys. Condens. Matters, , , 1999, . –k magnetostatic guided modes in ferromagnetic films, Phys. Lett. A, , , 1994, . Phase diagrams of a diluted Ising thin ferromagnetic film in a transverse field, Phys. Rev. B., , , 1995, . Phase diagrams of a diluted Ising ferromagnetic film with spin-1 in a transverse field, J. Phys. Condens. Matters, , , 1996, . 周期性调制稀释ISING 体系的相变,《物理学报>>,, , 1996, . Effects of eddy currents on retarded modes of antiferromagnets, Phys. Rev. B. , 1999, . Magnetostatic waves of metal magnetic/nonmagnetic superlattices, Phys. Rev. B. 61, , 2000, . Magnetostatic modes of a lateral antiferromagnetic/nonmagnetic superlattice, Phys. Rev. B., , , 1997, . Magnetostatic modes of antiferromagnet in a magnetic field nonmal to the surface, J. Magn. Magn. Materials, , 1999, . Magnetostatic surface and guided modes of lateral-magnetic-superlattice films,Phys. Rev. B. , , 1994, . Magnetostatic modes on lateral magnetic superlattices, Phys. Lett. A. , 1994, . Standing waves in a rectangular magnetic wire, Phys. Lett. A , 1995, . Magnetostatic modes of lateral magnetic-superlattice films in a transverse field, J. Phys. Condens. Matter, , 1997, . Magnetostatic modes of lateral magnetic superlattice in an applied field arbitrary direction, Phys. Rev. , , 1997, . Reflection and transmission by magnetic multilayers, J. Magn. Magn. Materials , 2000, . Transmission by antiferromagnetic-nonmagnetic multilayers, J. . Matter , , 1999, . Retarded modes of a lateral antiferromagnetic/nonmagnetic superlattices, Phys. Rev. B. , , 1995, . Surface retarded modes of magnetic superlattices with antiferromagnetic coupling, J. Magn. Magn. Materials, , , 2003, . Nonlinear magnetostatic surface waves of magnetic multilayers: Effective- medium theory, Phys. Rev. B. , , 2001, . Magnetostatic surface waves of lateral-magnetic superlattices, Phys. Lett. A. , 1999, . Xuan-Zhang Wang and Shu-Fang Fu, Dispersion properties of nonlinear bulk polaritons in uniaxial antiferromagnetic/nonmagnetic superlattices, J. Magn. Magn. Materals, , , 334(2004).37. Xuan-Zhang Wang and Hua Li, Nonlinear polaritons in antiferromagnetic superlattices, Phys. Rev. B,, , 054403 (2005).38. Xuan-Zhang Wang, The Faraday effect of an antiferromagnetic photonic crystal with a defect layer, J. Phys.: Condens. Matters, , , 5447 (2005).39. Jing Bai, Sheng Zhou, Feng-Li Liu and Xuan-Zhang Wang, Nonlinear infrared transmission through and reflection off antiferromagnetic films, J. Phys.: Condens. Matters, , 046217(2007).40. Rui-Hua Zhu, Cheng Jia and Xuan-Zhang Wang, Magnetostatic modes of a lateral ferromagnetic/ferromagnetic superlattice, Physics Letters A, , , 77 (2006)41.类维萍,贾城,王选章,涡流对侧向反铁磁/非磁超晶格中表面推迟模的影响,<<物理学报>> , 535(2008)42.Di Zhang, Jianing Ma, Hua Li, Shu-Fang Fu and Xuan-Zhang Wang, Anti-resonance of electron tunneling through a four-quantum-dot ring with two side-coupled quantum dots, Phys. Lett. A, , , 3085 (2008)43. Hong Gao, Zhou mingyu, Ji Hong, Xuan-Zhang Wang and Zhiguo Zhang, Synthesis and photoluminescence of Sb-induced ZnO nanowires along [0-1,1,1] with island attached, J. Alloy and Compounds, . 234-237 (2008).44. Hong Gao, Xitian Zhang, Mingyu Zhou, Zhiguo Zhang and Xuan-Zhang Wang, Nanohelices modified by SiO2 sheathed ZnO disks, Nanotechnology , 065601(2007)45. Yan Zhao, Hong Gao, Sheng Zhou, Hua Li Xuan-Zhang Wang, Nonlinear Response of Uniaxial Ferromagnets and Applications to Surface Magnetostatic Waves J. Magn. Magn. Materials, , , 2560-2567(2008)46. Zhou Sheng and Xuan-Zhang Wang, Method of enhancing second-harmonic generation of antiferromagnetic film, Journal of the Optical Society of America B, , , 1639-1644(2008).47. 宋玉玲,王选章, 一维受限反铁磁光子晶体的性质, <<光学学报>> No12 (2008)48. 尹永琦, 李华, 马佳宁, 贺泽龙, 王选章, 多端耦合量子点分子桥的量子输运特性研究, <<物理学报>> , 69(2009).49. Yu-Ling Song, Jing-Xing Ta, Hua Li and Xuan-Zhang Wang, Presence of left-handedness and negative refraction in antiferromagnetic/ionic-crystal multilayered films, J. Appl. Phys. , , 063119 (2009).50. Sheng Zhou, Hua Li, Shu-Fang Fu and Xuan-Zhang Wang, Second-Harmonic Generation from an antiferromagnetic film in one-dimension photonic crystals, Phys. Rev. B, , 205409 (2009) (12 pages)51. Jing-xiang Zhao, Yi-hong Ding, Qing-hai Cai, Xiao-guang Wang andXuan-Zhang Wang, Theoretical Studies of the Magnetism of the First-Row Adatom on the Silicon Carbide (SiC) Nanotube, J. Phys. Chemistry C , , 3825-3829 (2010)52. Jin-Xing Ta, Yu-Ling Song and Xuan-Zhang Wang, J. Appl. , 013520(2010)(4 pages)53. Shu Fang Fu, Jing Bai, Sheng Zhou, Xiu Rong Qu, Hua Li, Xuan Zhang Wang, Effects of molecular shape on polymeric liquid crystal, Key Engineering Materials, , 216-219(2010)54. Jing Bai, Shu Fang Fu and Xuan-zhang Wang, Dispersion properties of bulk polaritons in uniaxial antiferromagnetic film, Key Engineering Materials , 198-201 (2010)55. Jing Bai, Shu-Fang Fu, Sheng Zhou, Li Niu and Xuan-Zhang Wang, Nonlinear transmission through and reflection off antiferromagnetic sandwich, Materials Science Forum, (Optoelectronic materials), 995-998 (2010)56. Jing-Xiang Zhao, Yi-Hong Ding, Qing-Hai Cai, Xiao-Guang Wang, and Xuan-Zhang Wang, Chemical Functionalization of pyridine-like and porphyrin-like nitrogen-doped carbon nanotubes with transition metal atoms: A theoretical study, Theoretical Chemistry Accounts, (5-6), 727-733 (2010)57. Shu-Fang Fu and Xuan-Zhang Wang, Effects of magnetic field on shear stress of nematic liquid crystalline polymer under simple shear flow, Journal of Polymer Science: Part B48: Polymer Physics, (17), 1919-1926 (2010).58. Yu-Ling Song, Jin-Xing Ta and Xuan-Zhang Wang, Band gaps of two-dimensional antiferromagnetic photonic crystal, J. Appl. Phys. . 013525-5 (2011).59. Yan Zhao, Shu-Fang Fu and Xuan-Zhang Wang, Bistable transmission of antiferromagnetic Fabry-Perot resonator, J. Appl. Phys. . ,023512-6 (2011)59. Jing Bai, Shu-Fang Fu, Sheng Zhou and Xuan-Zhang Wang, Reflective optical bi-stability of antiferromagnetic films, The European Physical Journal B83, ,343-348(2011) Bo, Zhao J-x, Cai Qinghai, Wang Xiaoguang, and Wang Xuan-Zhang, Doping of Calcium in C60 Fullerence for enhancing CO2 capture and N2O Transformation: A Theoretical Study, J. Phys. Chem. A115 (36), 9969-9976(2011)61. Jin-Xiang Zhao, Yi-Hong Ding, Xiao-Gang Wang, Qing-Hai Cai, And Xuan-Zhang Wang, Diamond and Related Materials , 36-41(2011)62. Xuan-Zhang Wang and Hua Li, Nonlinear propagation of electromagnetic waves in antiferromagnets, in Propagation of Electromagnetic Waves in Complex Matter, edited by by Ahmed Kishk, (Intech-Open Access Publisher, 2011), . Zhao J-X, Gao Bo,Cai Qing-Hai, Wang Xiao-Guang, and Wang Xuan-Zhang,Theoretical study of phenol adsorption on the (8, 0) silicon carbide nanotube,Chemistry and Material Science : Theoretical Chemistry Accounts Vol29 , 85-92(2011).64. Dongmei Sun, Shufang Fu, Sheng Zhou and Xuan-Zhang Wang, Numerical simulation of optical bi-stability in antiferromagnetic sandwich structure, J. Magn. Magn. Materials, , , (2012)65. Jin-Xing Ta, Xuan-Zhang Wang, Optical properties of antiferromagnetic/ ion-crystal superlattices, J. Magn. Magn. Materials, , (2012) . Yu-Ling Song, Jin-Xing Ta and Xuan-Zhang Wang, High second-harmonic generation of antiferromagnetic/ion-crystal composite medium with negative refraction, J. Magn. Magn Materials , 1214-1217 (2012)67. Jin-Xing Ta and Xuan-Zhang Wang, Magneto-phonon polaritons in two-dimensional antiferromagnetic/ion-crystalic photonic crystal, Photonics and nanostructures-Fundamentals and Applications, (2012) . Yan Zhao, Shu-Fang Fu and Xuan-Zhang Wang, Nonlinear Far Infrared Transmission of Antiferromagnetic Fabry-Perot Resonator, IEEE Transaction on Magnetics, , 1597-1600(2012)69. 张强,周胜,厉强华,王选章,付淑芳,一维反铁磁光子晶体光学双稳效应研究,《物理学报》 , , 157501-7(2012)70. 周胜, 王选章,付淑芳,厉强华,曲秀荣,梁爽,张强,Voigt 位型下电介质/反铁磁体/电介质结构的二次谐波生成非倒易性研究,《物理学报》 , 187501-(2012)71. Shu-Fang Fu, Jing Bai and Xuan-Zhang Wang, Effects of magnetic field on discotic nematic liquid crystalline polymers under simple shear flow, Journal of Applied Polymer Science, (2012)72. Xuan-Zhang Wang, Coupled Edge Plasmon Modes of Metal/Dielectric Multi-Wedges, Chinese Physics B, (2013),accepted for publication73. Xuan-Zhang Wang and Yan Zhao, High Faraday effect of antiferromagnetic/ion- crystal photonic crystals in far infrared region, J. Appl. Phys. (2013), accepted for publication.

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Any survey of tax sources should begin with the nation’s fairest and most productive soure of revenue, the individual income tax. 任何税收来源的调查都应开始于国家最公正、生产性最强的国民收入来源--个人所得税. All advanced industrial countries levy a dircct tax on individual incomes, but nowhere is this tax as important as in the United States. In recent years,about 40 percent of federal cash receipts has been collected from this source. 所有先进的工业国家都对个人所得直接征税,但没有哪个国家在征此税时像美国一样重要。近年来,约40%的联邦现金收入都来源于此. The individual income tax is uniquely suited for raising revenue in a democratic country where the distribution of income, and therefore of ability to pay,is unequal. Theoreticians may disagree about the meaningfulness of the term “ability to pay,” but the close association between a man’s income and taxpaying ability is commonly accepted. There is also general acceptance of the idea of progression in income taxation. 个人所得税是非常适合民主国家增加国民收入的,在民主国家里收入分配和支付能力是不平等的. 理论家可能不赞成"支付能力"的长远意义,但个人收入和纳税能力间的密切关系却是普遍接受的. 级数所得税的观点也被普遍接受. The individual income tax has still another attractive feature. Income alone does not differentiate a man’s ability to pay—his family responsibilities are also important. A single person may be able to along on an income of $3000 a year, but a married man with two children would have great diffculty making ends meet. The individual income tax takes such differences into account through the personal exemptions and deductions, which are subtracted before arriving at the income subject to tax. 个人所得税还有另一个吸引人的特点. 收入不足以区分一个人的支付能力—他的家庭责任也是很重要的. 单身男士也许每年收入达3000美元, 但带着两个孩子的已婚男人要想收支相抵却很困难. 个人所得税通过个人豁免和扣除将这种差异解决了, 个人免税额在应纳税收之前就扣除了. The revenue potential of the individual income tax has been recognized only recently. For almost thirty years after its adoption in 1913, the tax applied mainly to a small group of high income people. Exemptions were high by current standards and few incomes were large enough rates. In the national effort to raise needed revenue during World War Ⅱ, exemptions were drastically were increased in 1946 and 1948,but have remained low by prewar standards. Tax rates were also raised in wartime, and have remained much higher than in earlier years. At the same time, personal incomes have continued to increase with the growth of the economy (and with the inflation that occurred during and after World WarⅡ and the Korean War). The combination of lower exemptions, higher rates, and higher incomes increased the yield of the individual income tax manyfold. In1939, tax liabilities were about $1 billion; in 1966, they are in excess of $50 billion. 个人所得税的收入潜力最近才得到公认. 在1913年实施后的30年里,个人所得税主要应用于一小部分高收入人士. 在现行标准下豁免是很高的,低收入者占很大的比率. 二战期间,国家努力增加收入,豁免急剧减少。1946年和1948年有所提高,但从战前的水准看,仍然很低。税率在战时也有人提出,但比起早些年仍高多了. 在此同时, 个人收入随经济增长继续增加,(也与其间和二战后的通货膨胀和朝鲜战争的因素) . 较低的豁免,高利率,高收入的结合成倍地增加了个人所得税. 1939年,纳税义务约为10亿美元; 但1966年,超过了500亿美元. This tremendous expansion could not have been possible without ready compliance with income tax laws and effective many countries where compliance is poor and administration is weak, there is great reluctance to rely heavily on the income tax. In this country, the record of compliance is good—although it can still be improved—and practical methods have been developed for administering a mass income tax (at a cost of only about 1/2 of 1 percent of tax collected). In the late 1930’s many people—even high-placed officials of the Internal Revenue Service—doubted that an income tax covering almost everyone could be administered effectively. Although some problems remain, in an advanced country the administrative feasibility of an individual income tax of almost universal coverage is no longer questioned. 没有所得税法律的遵守和有效的管理,这个巨大的扩张是不可能的。许多国家法律意识差,管理松散,过于依赖所得税就很困难. 在这个国家, 守法记录还好--虽然它仍可以得到改善--实用方法已制定用来管理大量所得税(按成本仅约为1%的税收额的1 / 2 ) . 在20世纪30年代后期,很多人甚至美国国内税局的高级官员都认为关系每个人的所得税应得到有效管理. 尽管一些问题依然存在, 在一个先进的国家个人所得税的几乎全面普及在行政上的可行性已不存在质疑. There are good economic reasons for using the income tax as a major source of revenue. The automatie flexibility of the income tax promotes economic stability and the progressive rates help prevent excessive concentration of economic power and control. Some believe that the income tax is also needed to moderate the growth of private savings of high income people, which is likely to hold down private demand for goods and believe that a high income tax impairs work and investment incentives and , therefore, reduces the nation’s economic growth. These are difficult questions which will be discussed later. Nonetheless, it is correct to say that the modern individual income tax. If carefully designed and well administered, is a powerful and essential economic instrument for a modern indusrtial econmy. 使用所得税作为财政收入主要来源有很好的经济原因. 该所得税的自动灵活性能促进经济稳定,累进税率有助于防止经济权力和控制过分集中. 有人认为所得税也需缓和高收入人群的私人储蓄增长, 这很可能压抑商品的服务的私人需求。有人认为高所得税降低工作和投资动力,因此,减少了国家的经济增长. 这些都是日后讨论的难题. 但是,现代的个人所得税是正确的. 如果经过精心设计和良好管理,是现代工业化经济的有力而必要的经济手段。 Structure of the Federal Income Tax 联邦所得税结构 The basic structure of the federal income tax is simple. The taxpayer adds up all his taxable sources of income, subtracts certain allowable deductions and exemptions for himself, his wife, children, and other dcpendents,and then applies the tax rates to the difference. But this procedure has many pitfalls for the taxpayer, and difficult questions of tax policy arise at almost every stage. Consequently, it is important to understand the main features of the income tax structure. 联邦所得税的基本结构是很简单的. 纳税人增添了他的一切应纳税收入,减去某些自己的、妻子的、孩子的和其他相关人的允许扣除和豁免权,然后适用税率差额. 但这种程序对纳税人也有很多陷阱,税收政策的难题几乎出现在每一阶段. 因此,了解所得税结构的主要特征是重要的. Adjusted Gross Income and Taxable Income调整过的总收入和应纳税收入 The two major concepts of income that appear on the tax return are: adjusted gross income and taxable income. 出现在纳税申报单上的两大收益好象是:调整过的总收入和应纳税收入. Adjusted gross income is the closest approach in tax law to what all economist might call “total income.” But it departs from an economic definition of income in some important respects. It represents the total income from all taxable sources, less certain expenses incurred in earning that income. In general, only money income is treated as taxable, but many items are excluded. Such exclusions include one-half of realized capital gains on assets held six months or more, interest on state and local government bonds,all transfer payments(for example,social security benefits and unemployment compensation), fringe benefits received by employees from their employers(the most important of these are contributions to pension plans), and income on savings through life insurance. The emphasis on money income automatically excludes unrealized capital gains and such imputed income as the rental value of owner-occupied homes. 在税法上调整的总收入是所有经济学家称之为"总收入"的最接近说法。 但是,在某些重要方面,它背离了收入的经济学定义. 它表示所有应纳税来源的总收入,较少的赚取收入中的确定开支. 一般说来,只有货币收入被视为应税的,但很多项目都被排除在外. 这种排除包括二分之一的持有六个月或以上的已实现资本收益,国家和当地政府公债的利息,所有的转移支付(例如,社会保障福利和失业补偿) , 雇员从其雇主那得到的附加福利(贡献中最重要的是为养老金计划) , 和加入了人寿保险的储蓄收入. 对货币收入的强调自动排除了未实现资本收益和这种像所有者租税价的推算收入. Adjusted gross income is used on the tax return in two ways. First, it is the income concept built into the simplified tax table, which is used for determining tax on more than 25 million returns. Second,it provedes the basis for placing limits on some of the personal deductions which are subrtacted in computing taxable income. 调整后的总收入用于纳税申报单有两种方式. 第一,它是收入概念建成的简易税表, 用于决定税收突破2500万美元的回报. 第二,它提供了限制某些个人扣除的基础,个人扣除在计算应纳税收入时已经减去了. Taxable income is computed by making two sets of deductions from adjusted gross income. The rirst are personal expenditures which are allowed as deductions by law—charitable contributions, interest paid,state-local income, general sales, property and gasoline taxes, medical and dental expenses above 3 percent of adjusted gross income, and casualty and theft losses above $100 for each lieu of these deductions, the taxpayer may use the standard deduction of 10 percent of adjusted gross income(with a minimum of $200 plus $100 for each exemption,and a maximum of $1000 for single persons and married persons filing joint returns and $500 for married couples filing separate returns). 应税收入是从调整过的总收入中制作两套扣除法计算而来的. 剩下的是法律允许扣除的个人支出--慈善捐款,所付利息,国有地方收入,一般销售 财产和汽油税, 高于调整后总收入3%的医疗及牙科服务费用, 伤亡和每次损失100美元以上的偷盗损失。代替上述扣减, 纳税人可使用10%调整后的总收入的标准扣除额 (最低200美元,加上每项豁免100美元,单身和夫妻联合备案的已婚人士每人最高1000美元,并返回500美元为已婚备案夫妻分开报税) . When the present standard deduction was first adopted in 1944, it was used by over 80 percent of the persons filing incomes have risen and deductible expenditures have increased,the percentage using the standard deduction has declined. In 1963, the standard deduction was still being used on million returns, or 56 percent of the million filed(Appendix Table C-6). But the amount of the standard deduction was small compared to home ownership, state-local taxes,and use of consumer credit, as well as the normal increase in expenditures that occurs as incomes rise. Total deductions reported on all 1963 returns amounted to $ billion; of this amount, $ billion were itemized deductions and $ billion were standard deduction. 现行标准扣除额首次在1944年应用时, 它被用于个人存档返还的80%以上.随着收入的增加和可扣除支出增加, 用于标准扣除额的比率也有所下降. 1963年标准扣除额仍被用于3580万的回报, 或6390万存档56% (附录表C 6 ) . 但征收的标准扣除额是比较小的,与国有、地方税,消费品信贷的使用, 以及随收入增加而不断增加的正常开支相比.1963年报告的总扣除额回到了592亿美元; 这一数额中, 有461亿美元详细说明了扣除项目,131亿美元为标准扣除额.

海洋生物来源药物先导化合物的研究进展【摘要】海洋生物中活性物质丰富,本篇文章对国内外近3年来从海洋生物中分离提取到的萜类化合物以及糖苷类化合物进行了归纳,并对其研究趋势进行了展望。这些新发现的萜类化合物广泛分布于海藻、珊瑚、海绵以及一些海洋真菌等海洋生物中,主要以单萜、倍半萜、二萜、三萜结构型式存在;而糖苷类化合物在海藻、海绵、海参、海星等海洋生物中发现大部分以糖苷脂、甾体糖苷、萜类糖苷型式存在。【关键词】海洋生物萜类化合物糖苷类生物活性【Abstract】.【Keywords】Marineorganism;terpenoid;glycoside;bioactivity海洋是生命之源,由于海洋环境的特殊性,具有高压、低营养、低温(特别是深海)、无光照以及局部高温、高盐等生命极限环境,海洋生物适应了海洋独特的生活环境,必然造就了海洋生物具有独特的代谢途径和遗传背景,必定也会有新的、在许多陆地生物中未曾发现过的新结构类型和特殊生物活性的化合物。萜类物质是一类天然的烃类物质,其分子中具有异戊二烯(C5H8)的基本单位。故凡由异戊二烯衍生的化合物,其分子式符合(C5H8)n通式的均称萜类化合物(terpenoids)或异戊二烯类化合物(isopenoids)。但有些情况下,在分子合成过程中由于正碳离子引起的甲基迁移或碳架重排以及烷基化、降解等原因,分子的某一片断会不完全遵照异戊二烯规律产生出一些变形碳架,它们仍属于萜类化合物。海洋生物中萜类化合物主要以单萜、倍半萜、二萜、二倍半萜为主,三萜和四萜种类和数量都较少,且大部分以糖苷形式存在。萜类化合物是海洋生物活性物质的重要组成部分,广泛分布于海藻、珊瑚、海绵、软体动物等海洋生物中,具有细胞毒性、抗肿瘤活性、杀菌止痛等活性作用。糖苷的分类有多种方法,按照在生物体内是原生的还是次生的可将其分为原生糖苷和次生糖苷(从原生糖苷中脱掉一个以上的苷称为次生苷或次级苷);按照糖苷中含有的单糖基的个数可将糖苷分为单糖苷、双糖苷、三糖苷等;按照糖苷的某些特殊化学性质或生理活性可将糖苷分为皂苷、强心苷等;按照苷元化学结构类型可分为黄酮糖苷、蒽醌糖苷、生物碱糖苷、三萜糖苷等,海洋类的糖苷大部分是按照此特点分类的,主要包括鞘脂类糖苷、甾体糖苷、萜类糖苷和大环内酯糖苷等,在很多海洋生物如海藻、珊瑚、海参、海绵等中均发现有糖苷类化合物存在。已有的研究表明海洋糖苷类成分大都具有抗肿瘤、抗病毒、抗炎、抗菌、增强免疫力等生物活性。抗白血病和艾氏癌药物阿糖胞苷Ara-C(D-arabinosylcytosine)1、抗病毒药物的Ara-A2以及Ara-C的N4-C16-19饱和脂肪酰基化衍生物3是海洋糖苷类药物成功开发的典范〔1〕。本篇文章对国内外自2005年来从海洋生物中分离提取到的萜类化合物以及糖苷类化合物进行了总结。1萜类化合物单萜2005年等人〔2〕对从红藻Plo

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