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   1344261篇
  免费   32455篇
  国内免费   10070篇
化学   674235篇
晶体学   20382篇
力学   75616篇
综合类   273篇
数学   242001篇
物理学   374279篇
  2021年   14073篇
  2020年   16481篇
  2019年   16608篇
  2018年   12646篇
  2016年   28318篇
  2015年   21364篇
  2014年   31308篇
  2013年   75360篇
  2012年   38606篇
  2011年   34875篇
  2010年   37377篇
  2009年   39864篇
  2008年   33930篇
  2007年   29079篇
  2006年   35967篇
  2005年   27734篇
  2004年   29227篇
  2003年   27884篇
  2002年   29057篇
  2001年   29344篇
  2000年   25351篇
  1999年   22945篇
  1998年   21334篇
  1997年   21353篇
  1996年   21417篇
  1995年   19459篇
  1994年   18902篇
  1993年   18314篇
  1992年   18529篇
  1991年   18747篇
  1990年   18003篇
  1989年   17979篇
  1988年   17605篇
  1987年   17541篇
  1986年   16421篇
  1985年   22777篇
  1984年   24011篇
  1983年   20093篇
  1982年   21710篇
  1981年   20942篇
  1980年   20258篇
  1979年   20563篇
  1978年   21792篇
  1977年   21475篇
  1976年   21093篇
  1975年   19784篇
  1974年   19381篇
  1973年   19796篇
  1972年   14335篇
  1967年   12617篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
The simple relation between representations of the covering groups of SL2 and GL2 makes it possible to fuse and extend the recent metaplectic results of Shimura, Waldspurger, Flicker, and ourselves. By giving a new (purely local andL-function theoretic) treatment of the Waldspurger-Shintani correspondence, we also simplify some of Waldspurger’s original results.  相似文献   
992.
The problem of the vector and axial-vector dominance of weak interactions within the framework of the quark model of superconductivity type is discussed.  相似文献   
993.
994.
Estimates of a rate of convergence of orderO(n –1) are obtained for integral functionals of an empirical process.Translated fromTeoriya Sluchainykh Protsessov, Vol. 15, pp. 10–16, 1987.  相似文献   
995.
Translated fromProblemy Ustoichivosti Stokhasticheskikh Modelei. Trudy Seminara, 1988, pp. 84–92.  相似文献   
996.
A mixed boundary-value problem for the nonlinear Schrödinger equation and its generalization is studied by the method used for the inverse scattering problem. A connection is established between conservation laws and boundary conditions in integrable boundary-value problems for higher nonlinear Schrödinger equations. It is shown that the generalized boundary-value problem requires a joint consideration of regular and singular solutions for the nonlinear Schrödinger equation with repulsion.Translated from Zapiski Nauchnykh Seminarov Leningradskogo Otdeleniya Matematicheskogo Instituta im. V. A. Steklova AN SSSR, Vol. 169, pp. 151–165, 1988.  相似文献   
997.
An algorithm is proposed for numerical construction of optimal programmed controls in the Mayer problem for a nonlinear dynamic system. In each step of the optimization process, the algorithm uses the method of successive linearization with subsequent projection of the objective functional gradient on the constraints and recovery of violated boundary conditions and constraints. Solutions of some test problems are reported.Translated from Vychislitel'naya i Prikladnaya Matematika, No. 56, pp. 107–114, 1985.  相似文献   
998.
The theory of tree-growing (RECPAM approach) is developed for outcome variables which are distributed as the canonical exponential family. The general RECPAM approach (consisting of three steps: recursive partition, pruning and amalgamation), is reviewed. This is seen as constructing a partition with maximal information content about a parameter to be predicted, followed by simplification by the elimination of ‘negligible’ information. The measure of information is defined for an exponential family outcome as a deviance difference, and appropriate modifications of pruning and amalgamation rules are discussed. It is further shown how the proposed approach makes it possible to develop tree-growing for situations usually treated by generalized linear models (GLIM). In particular, Poisson and logistic regression can be tree-structured. Moreover, censored survival data can be treated, as in GLIM, by observing a formal equivalence of the likelihood under random censoring and an appropriate Poisson model. Three examples are given of application to Poisson, binary and censored survival data.  相似文献   
999.
1000.
We present a stratification by “normal flatness” associated to an analytic mapping, analogous to Hironaka's classical result for analytic spaces. Our construction is based on a generic normal flatness theorem for mappings, proved using techniques concerning the variation of modules of meromorphically parametrized formal power series [1]. The existence of such a stratification was announced by Hironaka [13], but the other claims made in [13] are false. Counterexamples are also presented here.  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