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   1371685篇
  免费   25930篇
  国内免费   7783篇
化学   687872篇
晶体学   20438篇
力学   75192篇
综合类   110篇
数学   243897篇
物理学   377889篇
  2021年   13565篇
  2020年   15987篇
  2019年   16104篇
  2018年   13121篇
  2016年   28217篇
  2015年   20951篇
  2014年   30582篇
  2013年   74810篇
  2012年   39122篇
  2011年   36877篇
  2010年   37775篇
  2009年   39936篇
  2008年   35946篇
  2007年   32032篇
  2006年   37448篇
  2005年   30309篇
  2004年   31067篇
  2003年   29195篇
  2002年   30194篇
  2001年   30082篇
  2000年   25880篇
  1999年   23004篇
  1998年   21270篇
  1997年   21253篇
  1996年   21264篇
  1995年   19298篇
  1994年   18772篇
  1993年   18353篇
  1992年   18575篇
  1991年   18805篇
  1990年   18006篇
  1989年   18040篇
  1988年   17600篇
  1987年   17591篇
  1986年   16503篇
  1985年   22925篇
  1984年   24056篇
  1983年   20149篇
  1982年   21786篇
  1981年   21021篇
  1980年   20369篇
  1979年   20691篇
  1978年   21883篇
  1977年   21548篇
  1976年   21285篇
  1975年   19989篇
  1974年   19673篇
  1973年   20093篇
  1972年   14574篇
  1967年   12836篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
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   
92.
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   
93.
94.
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   
95.
Translated fromProblemy Ustoichivosti Stokhasticheskikh Modelei. Trudy Seminara, 1988, pp. 84–92.  相似文献   
96.
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   
97.
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   
98.
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   
99.
Using an integral theory of grating diffraction we calculate efficiencies greater than 100% if a coating with gain is taken into account. A connection with guided modes is conjectured. The application in optical computing seems to be possible.  相似文献   
100.
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