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   15962篇
  免费   643篇
  国内免费   146篇
化学   10488篇
晶体学   52篇
力学   330篇
综合类   1篇
数学   2943篇
物理学   2937篇
  2023年   142篇
  2022年   291篇
  2021年   350篇
  2020年   419篇
  2019年   496篇
  2018年   382篇
  2017年   295篇
  2016年   604篇
  2015年   565篇
  2014年   552篇
  2013年   926篇
  2012年   1087篇
  2011年   1285篇
  2010年   687篇
  2009年   569篇
  2008年   913篇
  2007年   835篇
  2006年   840篇
  2005年   775篇
  2004年   610篇
  2003年   471篇
  2002年   439篇
  2001年   240篇
  2000年   171篇
  1999年   186篇
  1998年   156篇
  1997年   167篇
  1996年   173篇
  1995年   147篇
  1994年   118篇
  1993年   102篇
  1992年   85篇
  1991年   76篇
  1990年   64篇
  1988年   46篇
  1987年   48篇
  1985年   70篇
  1984年   58篇
  1982年   61篇
  1981年   52篇
  1980年   48篇
  1979年   44篇
  1978年   47篇
  1977年   44篇
  1976年   55篇
  1968年   44篇
  1966年   69篇
  1964年   64篇
  1963年   72篇
  1962年   77篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
A nonlinear operator equation F(x)=0, F:HH, in a Hilbert space is considered. Continuous Newton’s-type procedures based on a construction of a dynamical system with the trajectory starting at some initial point x 0 and becoming asymptotically close to a solution of F(x)=0 as t→+∞ are discussed. Well-posed and ill-posed problems are investigated. Received: June 29, 2001; in final form: February 26, 2002?Published online: February 20, 2003 This paper was finished when AGR was visiting Institute for Theoretical Physics, University of Giessen. The author thanks DAAD for support  相似文献   
92.
93.
94.
95.
This work is devoted to the construction and investigation of two new classes of special functions, related to representations of groups of motions in the spaces of constant curvature as well as the unitary group of large ranks. These are special functions with matrix indices and some types of orthogonal polynomials in several continuous and discrete variables. The functions introduced generalize a number of classical scalar special functions in one variable.  相似文献   
96.
97.
We study the basic properties of the Maxwell equations for nonlinear inhomogeneous media. Assuming the classical nonlinear optics representation for the nonlinear polarization as a power series, we show that the solution exists and is unique in an appropriate space if the excitation current is not too large. The solution to the nonlinear Maxwell equations is represented as a power series in terms of the solution of the corresponding linear Maxwell equations. This representation holds at least for the time period inversely proportional to the appropriate norm of the solution to the linear Maxwell equation. We derive recursive formulas for the terms of the power series for the solution including an explicit formula for the first significant term attributed to the nonlinearity.  相似文献   
98.
The antigen-antibody interaction between coproporphyrin I and anti-coproporphyrin antibodies was studied by a fluorescence method in water and a reverse micellar system: n-octane/Aerosol OT. Coproporphyrin fluorescence was quenched, and coproporphyrin emission maximum was shifted to the long-wavelength region after binding to the antibodies or Fab-fragments. The mechanism of this quenching is static, most probably, by a tryptophan residue (or maybe lysine or methionine). Apparent dynamic quenching, in this case, arises from protein backbone motion. A special kind of antibody Fab-Fab dimerization was proposed.  相似文献   
99.
An abstract treatment of Bell inequalities in proposed, in which the parameters characterizing Bell's observable can be times rather than directions. The violation of a Bell inequality might then be taken to mean that a property of a system can be changed by the timing of a distant measurement, which could take place in the future.  相似文献   
100.
The material tensor of linear response in electrodynamics is constructed out of products of two symmetric second rank tensor fields which in the approximation of geometrical optics and for uniaxial symmetry reduce to “optical” metrics, describing the phenomenon of birefringence. This representation is interpreted in the context of an underlying internal geometrical structure according to which the symmetric tensor fields are vectorial elements of an associated two-dimensional space.  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