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   277085篇
  免费   2273篇
  国内免费   874篇
化学   133379篇
晶体学   4391篇
力学   14535篇
综合类   11篇
数学   50342篇
物理学   77574篇
  2020年   1724篇
  2019年   1918篇
  2018年   12371篇
  2017年   12305篇
  2016年   9410篇
  2015年   2991篇
  2014年   3817篇
  2013年   9348篇
  2012年   10085篇
  2011年   18067篇
  2010年   11103篇
  2009年   11484篇
  2008年   13463篇
  2007年   15499篇
  2006年   6881篇
  2005年   7278篇
  2004年   6953篇
  2003年   6959篇
  2002年   5810篇
  2001年   6359篇
  2000年   4888篇
  1999年   3653篇
  1998年   2917篇
  1997年   2832篇
  1996年   2779篇
  1995年   2549篇
  1994年   2402篇
  1993年   2250篇
  1992年   2875篇
  1991年   2787篇
  1990年   2720篇
  1989年   2746篇
  1988年   2771篇
  1987年   2775篇
  1986年   2648篇
  1985年   3348篇
  1984年   3351篇
  1983年   2633篇
  1982年   2750篇
  1981年   2799篇
  1980年   2578篇
  1979年   2917篇
  1978年   2892篇
  1977年   2998篇
  1976年   2832篇
  1975年   2568篇
  1974年   2519篇
  1973年   2488篇
  1972年   1718篇
  1968年   1713篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
51.
This primer provides a self-contained exposition of the case where spatial birth-and-death processes are used for perfect simulation of locally stable point processes. Particularly, a simple dominating coupling from the past (CFTP) algorithm and the CFTP algorithms introduced in [13], [14], and [5] are studied. Some empirical results for the algorithms are discussed. Received: 30 June 2002  相似文献   
52.
The structural evolution in amorphous silicon and germanium thin films has been investigated by high-resolution transmission electron microscopy (HRTEM) in conjunction with autocorrelation function (ACF) analysis. The results established that the structure of as-deposited semiconductor films is of a high density of nanocrystallites embedded in the amorphous matrix. In addition, from ACF analysis, the structure of a-Ge is more ordered than that of a-Si. The density of embedded nanocrystallites in amorphous films was found to diminish with annealing temperature first, then to increase. The conclusions also corroborate well with the results of diminished medium-range order in annealed amorphous films determined previously by a variable coherence microscopy method.  相似文献   
53.
We consider complete ideals supported on finite sequences of infinitely near points, in regular local rings with dimensions greater than two. We study properties of factorizations in Lipman special *-simple complete ideals. We relate it to a type of proximity, linear proximity, of the points, and give conditions in order to have unique factorization. Several examples are presented. Received: 2 February 2000 / in final form: 14 March 2001 / Published online: 18 January 2002  相似文献   
54.
55.

An A-loop is a loop in which every inner mapping is an automorphism. A problem which had been open since 1956 is settled by showing that every diassociative A-loop is Moufang.

  相似文献   

56.
The principal physics goals of the Compact Muon Solenoid experiment under construction at the Large Hadron Collider at CERN in Geneva are reviewed. Procedures to search for the Standard Model Higgs boson, supersymmetric Higgses and other supersymmetric particles are described.  相似文献   
57.
The scattering of heavy ion with a multilevel Rydberg atom in the presence of an electromagnetic field is studied. The interaction of Rydberg atom and the e.m field is explored using non-perturbative quasi-energy technique. Although the results are presented for selected excitations but in actual calculations we have included many levels of the atom. The effect of various parameters are shown on collisional excitation process. As an illustration detailed calculations are performed for the inelastic proton-Na Rydberg atom collision accompanied by the transfer of photons and the effects of dressing due to the field are considered. The emphasis of the present work is on collision induced transitions especially the case that involves change of orbital as well as principal quantum number. Received 26 December 2001 / Received in final form 8 April 2002 Published online 19 July 2002  相似文献   
58.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 55, No. 4, pp. 624–629, October, 1991.  相似文献   
59.
60.
Partially supported by the general research fund at the University of Kansas  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