impossible between members of different species because genitals of males and females are structurally incompatible or because molecules on the surfaces of sperm and egg fail to A final type of prezygotic mechanism is temporal isolation, in which time-related environmental cues that trigger reproductive processes are different for related 有时,产生前合子隔离的差异涉及了隔离机制。即,由于生殖器结构不匹配或精卵分子表面不结合而使不同种群成员间不能自然结合。最后一类前合子机制是暂时隔离,与时间有关的环境因素触发了相关物种的不同繁殖过程。
1In the first study to look at what happens over the years to the billions of pounds of plastic waste floating in the world's oceans, scientists are reporting that plastics — reputed to be virtually indestructible — decompose with surprising speed and release potentially toxic substances into the 2Chemicals are an important aspect in our economy and serves with many However, when chemicals are not properly used they can create a problem with global There is the threat of chemical spills and also a possible use by Many chemicals are stored and processed at numerous If terrorists were to attack any chemical plants in the United States it would kill more than 2 million There is also a long-term threat of contamination that will affect both people and the These chemicals can contaminate the water and cause many illnesses to In 1962, Rachel Carson informed the public about the horrible effects that DDT had on the environment and health problems of But it took 10 years for the United States to ban this But not all chemicals pose a security To reduce the use of chemicals facilities are required to provide the public with annual chemical This has allowed our society to force these facilities to use these chemicals better and The Stockholm Convention on Persistent Organic Pollutants came into effect in May This treaty would ban or restrict the production and use of 12 hazardous There will always be an abundance of chemicals but their use needs to be lowered to make them less of a 3A captain of a ship drunkenly crashes a massive oil tanker along a reef and changes the physical and emotional world Chemical spills are major problems that plague the Strict government regulation is trying to aid with this problem, but governmental leaders face many Disposal of harmful chemicals is often difficult and Since chemical waste has destroyed the environment, steps are being taken to prevent further 看看,参考一下吧:
有机化学英语论文Abstract In this work the effects of the microporosity and chemical surfaceof polymeric adsorbents on adsorptive properties of phenol Textural parameters of four kinds of polymeric resins namely AB-8 D4006 NKA-II and D16 resin were separately measuredby ASAP The surface chemistry of these polymeric resins was determined by means of inverse gaschromatography (IGC) and diffusereflectance infrared Fourier transform spectroscopy (DRIFTS) Static equilibrium adsorption experiments were carried out to obtain theisotherms of phenol on the polymeric It was shown that NKA-II and AB-8 resin possessed relatively high BET surface areas andmicropore volumes while D4006 and D16 resin possessed comparatively low BET surface areas and micropore The results of IGCexperiments revealed that NKA-II resin had extraordinary high specific component of the free energy of adsorption both for polar acetone andbenzene probe and thus extraordinary strong surface polarity compared to the other polymeric It was also found that the isotherm ofphenol on NKA-II was much higher than that on the other polymeric resins due to its strongest surface polarity and largest micropore volumeamong four kinds of These experimental observations indicated that adsorption of phenol on the polymeric resins depended greatly ontheir microporosity and surface The well-developed microporosity and the strong surface polarity would improve the adsorptionof phenol on the polymeric 2004 Elsevier BV All rights Keywords: Polymeric resin; Phenol; Porosity; Surface chemistry; Inverse gas chromatography
首先,可以先看看格林童话及安徒生童话,这些童话故事都耳熟能详的,有利于扩大词汇量,提高阅读速度;然后,再看看劳伦斯的《儿子与情人》(《Sonsandlovers》),这篇文章既不是太难又很经典;最后,再看看一些名著,最好是你已看过中文版的英文原著
《新概念英语1~4册》,作者亚历山大、何承恩。
给我汉字 Funds are the lifeblood of our ability to operate normally, while the fund management has become the core content of corporate Finance and Accounting is exclusively through certain technical means and methods of accounting for funds, and specifically for corporate governance, decision-making accounting information in a As we all know, with the continuous development of the economy, financial accounting in the management, decision-making in an increasingly important Accordingly, the financial accounting of quality, a direct impact on the managers, operators, investors and the public interest, but also affect the company's economic, social image and social credibility, and therefore the process of socio-economic operations irreplaceable Enterprise Management is designed to achieve maximum benefits in the enterprise, that is a great honor to bring to the enterprise, and the various enterprises will realize the healthy and sustainable Business operations and financial condition is through the balance sheet, income statement, cash flow statement and The accounting department directly through the corporate accounting, business conditions and results for effective financial analysis, not only to promote enterprise managers can quickly understand how much of the current corporate profits and the level of debt capacity, but also can be found Enterprise The size of the risks, pros and cons of corporate capital structure, so that the operators use many aspects of the enterprise to make the right decisions, with minimal risk, the most healthy financial position to achieve the maximum profit the At the same time, you can also find some essential issues, in order to improve management to provide the basis of some relevant
推荐到OA图书馆,可免费下载全文。输入英文关键词即可。
维普网,万方网
中文文献:CNKI中国知网, 或者你们学校数据库里去找。 外文文献:ISI WEB KNOWLEDGE, ,这里含所有有用文献的90%以上。 或者你可以根据文献的参考文献去各大期刊网站直接搜,如google一下chemical review,它就属于ACS,到那上面去找就可以了。 一般来说这些数据库的文献能不能下都要看你的学校有没有买这个权限了,如果没上大学的话,去找大学的师兄师姐要个号就好了。 化学品的物性去化工引擎 科普性质的东西一般WIKI一下或者 也能找到一些。 还有IUPAC的网好像是随便上的 其它的具体还想知道什么随时提问!
如果在学校,可以进入学校网站的图书资源进行文献检索。其他很多有关的网站要注册会员,免费的不好找,一般都是付费的。
论文文献综述怎么写