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   8152篇
  免费   173篇
  国内免费   25篇
化学   5988篇
晶体学   45篇
力学   78篇
数学   1176篇
物理学   1063篇
  2020年   78篇
  2019年   77篇
  2016年   153篇
  2015年   154篇
  2014年   120篇
  2013年   271篇
  2012年   257篇
  2011年   335篇
  2010年   194篇
  2009年   199篇
  2008年   310篇
  2007年   323篇
  2006年   290篇
  2005年   318篇
  2004年   302篇
  2003年   245篇
  2002年   203篇
  2001年   119篇
  2000年   118篇
  1999年   112篇
  1998年   113篇
  1997年   135篇
  1996年   136篇
  1995年   132篇
  1994年   127篇
  1993年   131篇
  1992年   127篇
  1991年   114篇
  1990年   94篇
  1989年   122篇
  1988年   128篇
  1987年   114篇
  1986年   123篇
  1985年   142篇
  1984年   113篇
  1983年   113篇
  1982年   117篇
  1981年   105篇
  1980年   119篇
  1979年   106篇
  1978年   98篇
  1977年   95篇
  1976年   86篇
  1974年   100篇
  1973年   86篇
  1971年   81篇
  1961年   141篇
  1960年   196篇
  1959年   103篇
  1958年   115篇
排序方式: 共有8350条查询结果,搜索用时 15 毫秒
101.
102.
Gold     
Ohne Zusammenfassung  相似文献   
103.
104.
105.
106.
107.
Theoretical vibronic S1S0 line spectra of the isomeric phenyl naphthalenes calculated within the Condon as well as the Herzberg-Teller approaches on the basis of completely optimizedS 0 andS 1 molecular geometries, are presented and are contrasted with the experimental fluorescence spectra. The theory-experiment comparison is successful only within the Herzberg-Teller approximation by explicitly including the Dushinsky transformation. An analysis of the significant vibrational modes is given.  相似文献   
108.
For a great number of processes of technical importance (separation precipitating, adsorption and chemical conversion) an indication of progress of reaction without any temporal delay and gap is required with regard to process optimation. Beside and in addition to thermal analyses and optical methods electrical methods can be used, which depend on measuring of those electric properties, which are connected with each change of phases of the material under test. By use of potentials of medium or high frequency the cell of reaction is free of test probes. This is especially favourable for investigations of such mixtures of phases, in which the surfaces of electrodes would be changed irreversible by sedimentation or separation of phase. In this way the following reactions were studied: precipitation processes in supersaturated aqueous solutions, solution of crystals of potassium chloride, adsorption of alkali solution by ground quartz, sedimentation of mineral substances, separation processes of the system phenol-water and transformation of high polymers.  相似文献   
109.
A soluble, bifunctional enzyme complex has been prepared by crosslinking lactate dehydrogenase and alcohol dehydrogenase with glutaraldehyde. The crosslinking was performed on a solid phase while the active sites of alcohol dehydrogenase and lactate dehydrogenase were held adjacent to one another with the aid of a bis-NAD analog. Subsequently, the enzyme complex was released from the solid phase. The soluble enzyme complex was then purified by using NAD-Sepharose as an affinity adsorbent. Based on gel filtration experiments, the complex was estimated to consist of one of each dehydrogenase. By using a third enzyme, lipoamide dehydrogenase, which competes with lactate dehydrogenase for NADH produced by alcohol dehydrogenase, the effect of site-to-site orientation was studied. It was found that about 83% of the NADH produced by alcohol dehydrogenase was oxidized by site-to-site oriented lactate dehydrogenase compared to a figure of only about 61% obtained in an identical system of separate enzymes. This indicates that given two alternative routes, the preference for the one to lactate dehydrogenase over the one to lipoamide dehydrogenase is enhanced when lactate dehydrogenase and alcohol dehydrogenase are site-to-site oriented.  相似文献   
110.
The information gained in the context of extrapolating the correlation energy by intrinsic scaling is used to shorten the full configurational expansions of electronic wave function without compromising their chemical accuracy. The truncations are accomplished by judiciously limiting the participation of the ranges of predetermined approximate sets of natural orbitals in the various excitation categories.  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