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   19921篇
  免费   2213篇
  国内免费   2038篇
化学   2246篇
晶体学   30篇
力学   1748篇
综合类   502篇
数学   13591篇
物理学   6055篇
  2024年   25篇
  2023年   165篇
  2022年   328篇
  2021年   358篇
  2020年   412篇
  2019年   423篇
  2018年   444篇
  2017年   575篇
  2016年   644篇
  2015年   500篇
  2014年   1012篇
  2013年   1282篇
  2012年   1038篇
  2011年   1261篇
  2010年   1118篇
  2009年   1377篇
  2008年   1342篇
  2007年   1430篇
  2006年   1283篇
  2005年   1225篇
  2004年   1004篇
  2003年   916篇
  2002年   766篇
  2001年   710篇
  2000年   655篇
  1999年   561篇
  1998年   509篇
  1997年   478篇
  1996年   347篇
  1995年   283篇
  1994年   236篇
  1993年   179篇
  1992年   152篇
  1991年   125篇
  1990年   136篇
  1989年   91篇
  1988年   86篇
  1987年   75篇
  1986年   67篇
  1985年   82篇
  1984年   66篇
  1983年   46篇
  1982年   63篇
  1981年   59篇
  1980年   38篇
  1979年   34篇
  1978年   30篇
  1977年   26篇
  1976年   30篇
  1973年   21篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
In this paper, we obtain some normality criteria for families of meromorphic functions that concern the exceptional functions of derivatives.  相似文献   
62.
We obtain asymptotic lower bounds for the spectral function of the Laplacian and for the remainder in local Weyl’s law on manifolds. In the negatively curved case, thermodynamic formalism is applied to improve the estimates. Key ingredients of the proof include the wave equation parametrix, a pretrace formula and the Dirichlet box principle. Our results develop and extend the unpublished thesis of A. Karnaukh [Ka]. The first author was supported by NSERC, FQRNT, Alfred P. Sloan Foundation Fellowship and Dawson Fellowship. The second author was supported by NSERC and FQRNT. Received: April 2006 Revision: October 2006 Accepted: October 2006  相似文献   
63.
We investigate a multicomponent anisotropic liquid system. The first spatial moment of the direct correlation function is taken into account to obtain asymptotic expressions for the pairwise correlation functions. In this approximation, we obtain the pairwise correlation functions that describe the system behavior not only in the critical-state neighborhood but also in the noncritical domain. We show that the critical parameters for the anisotropic system differ from those for the isotropic system.  相似文献   
64.
New variants of the generalized level method for minimization of convex Lipschitz functions on a compact set with a nonempty interior are proposed. These variants include the well-known generalized and classical level methods. For the new variants, an estimate of the convergence rate is found, including the variants in which the auxiliary problems are solved approximately.  相似文献   
65.
For any given positive integer n≥1,the Euler functionφ(n) is defined to be the number of positive integers not exceeding n,which is relatively prime to n.ω(n) is defined to be the number of different prime divisors of n.In order to know the solvability of the function ofφ(φ(φ(n)))=2~(ω(n)),properties of the number theoretical functionφ(φ(n)) is studied in the paper.  相似文献   
66.
Recently we established Matysiak and Szablowski's conjecture [V. Matysiak, P.J. Szablowski, Theory Probab. Appl. 45 (2001) 711-713] about a lower bound of real-valued characteristic functions. In this paper, applying an alternative approach we are able to give explicitly the ranges of argument for which the obtained inequalities hold true for general characteristic functions.  相似文献   
67.
We extend results on square integrable representations of a locally compact group to subrepresentations of a representations induced from a character of a closed subgroup. We do so working in the framework of quotient representations of ∗-algebras.  相似文献   
68.
In the present paper, we consider the problem of the optimal reconstruction of the solution of the wave equation from the approximate values of the Fourier coefficients of the function specifying the initial form of the string. For an operator defined on the weight space of vectors from l 2, we present the solution of the more general problem of reconstruction from the approximate values of the coordinates of these vectors.  相似文献   
69.
We obtain asymptotic formulas for non-self-adjoint operators generated by the Sturm-Liouville system and quasiperiodic boundary conditions. Using these asymptotic formulas, we obtain conditions on the potential for which the system of root vectors of the operator under consideration forms a Riesz basis.  相似文献   
70.
We consider generalizations of Pólya’s theorem to the case of entire functions taking algebraic values at natural or integer points.  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