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   494篇
  免费   3篇
化学   269篇
晶体学   1篇
力学   64篇
数学   112篇
物理学   51篇
  2022年   3篇
  2021年   13篇
  2020年   2篇
  2019年   4篇
  2018年   6篇
  2017年   2篇
  2016年   12篇
  2015年   12篇
  2014年   11篇
  2013年   14篇
  2012年   22篇
  2011年   28篇
  2010年   21篇
  2009年   17篇
  2008年   28篇
  2007年   36篇
  2006年   22篇
  2005年   20篇
  2004年   23篇
  2003年   18篇
  2002年   13篇
  2001年   6篇
  2000年   10篇
  1999年   5篇
  1998年   3篇
  1997年   7篇
  1996年   8篇
  1995年   5篇
  1994年   5篇
  1993年   8篇
  1992年   8篇
  1991年   5篇
  1990年   5篇
  1989年   6篇
  1988年   4篇
  1987年   2篇
  1986年   8篇
  1985年   7篇
  1984年   9篇
  1983年   10篇
  1982年   6篇
  1981年   7篇
  1980年   6篇
  1979年   7篇
  1977年   6篇
  1976年   3篇
  1975年   4篇
  1969年   3篇
  1967年   1篇
  1958年   1篇
排序方式: 共有497条查询结果,搜索用时 0 毫秒
491.
A Car-Parrinello molecular dynamics simulation has been performed on a solution of Br- in liquid methanol analyzing with particular attention charge transfer and polarization effects. The first solvation shell has been characterized in terms of H-bonds, and it has been found that the high polarization of the bromide gives rise to a stable solvent cage. The differences in the coordination number with the chloride can be ascribed to the ionic radius and to the stronger perturbations brought by the solvent to the bromide ion.  相似文献   
492.
The mass spectrometric behaviour of a series of 6,6-disubstituted dibenzo(d,f)(1,3)dioxepine derivatives have been studied. The fragmentation patterns were described and discussed in detail with the aid of labelled compounds, accurate mass measurements and collisionally induced dissociation experiments performed using an ion trap.  相似文献   
493.
The chemical origin of the norrisolide-induced irreversible Golgi vesiculation was studied using a variety of norrisolide probes. This natural product was found to bind to a receptor on the Golgi membranes using the perhydroindane core fragment as the recognition element. The acetylated gamma-lactol-gamma-lactone side chain of norrisolide is essential for the irreversible Golgi vesiculation and can be replaced by other electrophilic motifs without loss of biological function. In particular, compound 10 reproduces the cellular phenotype of the natural product.  相似文献   
494.
Selected topics in strangeness nuclear physics are critically reviewed. This includes production, structure and weak decay of ??-Hypernuclei, the $\bar K$ nuclear interaction and the possible existence of $\bar K$ bound states in nuclei. Perspectives for future studies on these issues are also outlined.  相似文献   
495.
We recently developed a novel composite photopolymerizable material which allows the holographic recording of diffraction gratings with optimal optical and mechanical properties (high diffraction efficiency, transparency and spatial resolution, low shrinkage, long time stability). This material was successfully used to produce a low cost and easy to make optically pumped, organic distributed feedback laser, working on the first diffraction order of a high quality Bragg grating doped with a photoluminescent dye. Here we show the possibility of positioning these micrometer sized light sources at any point of a generic lab-on-a-chip device by borrowing experimental techniques commonly used in the fields of microfluidics and optofluidics. In particular, a microfluidic channel has been imprinted by soft lithography in a polydimethylsiloxane substrate in order to convey the photopolymerizable mixture to a particular area of the sample, where the laser device has been holographically recorded. A characterization of the lasing properties of this device has been carried out. The proposed approach allows a better confinement of the emitted light and overcomes some physical constrains (resolution, aspect ratio) of PDMS based microfluidic laser thus opening new possibilities for the complex integration of organic laser sources in lab-on-a-chip devices.  相似文献   
496.
497.
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