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   64篇
  免费   1篇
  国内免费   1篇
化学   23篇
数学   19篇
物理学   24篇
  2018年   2篇
  2017年   1篇
  2016年   1篇
  2014年   3篇
  2013年   3篇
  2012年   2篇
  2011年   6篇
  2010年   5篇
  2009年   2篇
  2008年   3篇
  2007年   5篇
  2006年   4篇
  2005年   1篇
  2004年   3篇
  2003年   3篇
  2002年   3篇
  2001年   3篇
  1999年   1篇
  1998年   1篇
  1996年   1篇
  1994年   1篇
  1993年   1篇
  1992年   5篇
  1991年   1篇
  1986年   1篇
  1985年   1篇
  1984年   1篇
  1982年   2篇
排序方式: 共有66条查询结果,搜索用时 109 毫秒
11.
12.
The change in the fraction of positrons forming positronium in an oscillating electric field is measured in n-pentane, n-hexane and n-decane. Positron mobilities, at room temperature, of 6, 8.5 and 11.5cm2/V are found for the three liquids. The results are discussed in the light of the Ore model and the spur model of positronium production.  相似文献   
13.
14.
Evidence for a reaction between aluminium and SiO2 film is presented using Auger electron spectroscopy (AES) and low-energy electron-loss spectroscopy (ELS) techniques. This reaction is studied in situ during the manufacture of metal insulator semiconductor devices (MIS), under ultra-high vacuum conditions (UHV). A reduction of the SiO2 film upon aluminization occurs, even at room temperature, giving rise to a complex interface.ERA CNRS n° 899ERA CNRS n° 373  相似文献   
15.
The self-assembly of monodispersed supramolecular nanoclusters was observed by scanning tunneling microscopy (STM). The clusters form from the naturally occurring amino acid cysteine by vapor deposition onto the Au(110)-(1 x 2) surface under ultrahigh vacuum conditions. Enantiomerically pure l- and d-cysteine yields clusters with mirror-image STM signatures. Racemic ld-cysteine segregates into homochiral clusters, evidencing specific intermolecular interactions during the self-assembly process.  相似文献   
16.
Establishing a molecular-level understanding of enantioselectivity and chiral resolution at the organic-inorganic interfaces is a key challenge in the field of heterogeneous catalysis. As a model system, we investigate the adsorption geometry of serine on Cu{110} using a combination of low-energy electron diffraction (LEED), scanning tunneling microscopy (STM), X-ray photoelectron spectroscopy (XPS), and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. The chirality of enantiopure chemisorbed layers, where serine is in its deprotonated (anionic) state, is expressed at three levels: (i) the molecules form dimers whose orientation with respect to the substrate depends on the molecular chirality, (ii) dimers of L- and D-enantiomers aggregate into superstructures with chiral (-1 ?2; 4 0) lattices, respectively, which are mirror images of each other, and (iii) small islands have elongated shapes with the dominant direction depending on the chirality of the molecules. Dimer and superlattice formation can be explained in terms of intra- and interdimer bonds involving carboxylate, amino, and β-OH groups. The stability of the layers increases with the size of ordered islands. In racemic mixtures, we observe chiral resolution into small ordered enantiopure islands, which appears to be driven by the formation of homochiral dimer subunits and the directionality of interdimer hydrogen bonds. These islands show the same enantiospecific elongated shapes those as in low-coverage enantiopure layers.  相似文献   
17.
18.
吴世晖  余定伟  厉振虹  JONES  M.  JR. 《化学学报》1986,44(1):67-71
用锂有机物的方法合成了四种含有环丙基有机硅化合物,对上述每种化合物中可能存在着的立体异构进行了分离和和构型测定。  相似文献   
19.
We describe algorithms for two-stage stochastic linear programming with recourse and their implementation on a grid computing platform. In particular, we examine serial and asynchronous versions of the L-shaped method and a trust-region method. The parallel platform of choice is the dynamic, heterogeneous, opportunistic platform provided by the Condor system. The algorithms are of master-worker type (with the workers being used to solve second-stage problems), and the MW runtime support library (which supports master-worker computations) is key to the implementation. Computational results are presented on large sample-average approximations of problems from the literature.  相似文献   
20.
We have studied the diffusion of the two organic molecules DC and HtBDC on the Cu(110) surface by scanning tunneling microscopy. Surprisingly, we find that long jumps, spanning multiple lattice spacings, play a dominating role in the diffusion of these molecules--the root-mean-square jump lengths are as large as 3.9 and 6.8 lattice spacings, respectively. The presence of long jumps is revealed by a new and simple method of analysis, which is tested by kinetic Monte Carlo simulations.  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