首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   325篇
  免费   11篇
化学   251篇
晶体学   2篇
力学   2篇
数学   56篇
物理学   25篇
  2024年   1篇
  2023年   3篇
  2022年   9篇
  2021年   24篇
  2020年   15篇
  2019年   14篇
  2018年   10篇
  2017年   9篇
  2016年   9篇
  2015年   15篇
  2014年   13篇
  2013年   14篇
  2012年   24篇
  2011年   19篇
  2010年   11篇
  2009年   15篇
  2008年   14篇
  2007年   28篇
  2006年   17篇
  2005年   15篇
  2004年   12篇
  2003年   7篇
  2002年   9篇
  2001年   2篇
  2000年   1篇
  1999年   3篇
  1998年   4篇
  1997年   1篇
  1996年   2篇
  1995年   2篇
  1994年   2篇
  1992年   2篇
  1990年   2篇
  1985年   1篇
  1980年   1篇
  1979年   2篇
  1977年   1篇
  1976年   1篇
  1974年   1篇
  1965年   1篇
排序方式: 共有336条查询结果,搜索用时 0 毫秒
331.
Huang used the methods of Rogers, Watson and Bressoud to derive some new modular relations involving the Göllnitz-Gordon functions. In this paper, using Ramanujan’s modular equations, we present a uniform method to prove these modular relations established by Huang.  相似文献   
332.
The conformation of copper “funnel” complexes that contains a coordinating appended arm can be electrochemically switched between endo, which corresponds to the self‐coordination of the arm through the cavity, and exo positions. This process, which is reminiscent of a cup‐and‐ball device, is activated by an exogenous ligand for complexes that contain a hydroxy‐terminated arm. The exchange is electrochemically triggered and is operated in either CuI or CuII redox states, depending on the exogenous ligand, that is, CO or n‐butylamine, respectively.  相似文献   
333.
Periodica Mathematica Hungarica - Let $$\bar{p}(n)$$ denote the number of overpartitions of n. Recently, numerous congruences modulo powers of 2, 3 and 5 were established regarding $$\bar{p}(n)$$ ....  相似文献   
334.
The filamentous fungus Fusarium oxysporum is known for its ability to ferment xylose-producing ethanol. However, efficiency of xylose utilization and ethanol yield was low. In this study, the transaldolase gene from Saccharomyces cerevisiae has been successfully expressed in F. oxysporum by an Agrobacterium tumefaciens-mediated transformation method. The enzymatic activity of the recombinant fungus (cs28pCAM-Sctal4) was 0.195 times higher than that of the wild-type strain (cs28). The recombinant strain also exhibited a 28.83% increase in ethanol yield on xylose media compared to the parental strain. Enhanced ethanol production and a reduction in the biomass were observed during xylose fermentation. Ethanol yield from rice straw by simultaneous saccharification and fermentation with cs28pCAM-Sctal4 was 0.25 g?g?1 of rice straw. The transgenic strain of F. oxysporum cs28pCAM-Sctal4 might therefore have potential applications in industrial bioenergy production.  相似文献   
335.
Journal of Solid State Electrochemistry - The aim of this work was to study the effect of a RuO2 support on the activity of Pd nanoparticles for formic acid oxidation, comparing the results with...  相似文献   
336.
The synthesis of primary amine end‐functional poly(tert‐butyl acrylate)s has been achieved by using the Gabriel reaction. Polymerization of tert‐butyl acrylate was first achieved by atom transfer radical polymerization using ethyl‐2‐bromoisobutyrate or paramethoxyphenyl‐2‐bromoisobutyrate as initiator. Both resulting polymers, with a bromide‐end atom, were converted into phthalimido intermediates which then were successfully hydrolyzed using potassium hydroxide in tert‐butyl alcohol to result in poly(tert‐butyl acrylate)s terminated by a primary amine function. End group interconversions were followed by 1H NMR, FT‐IR, and MALDI‐TOF MS measurements. All the results proved that quantitative transformations were achieved at each step. Moreover, the method developed is very easy to carry out.

  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号