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   1375266篇
  免费   25946篇
  国内免费   7848篇
化学   693310篇
晶体学   20130篇
力学   75251篇
综合类   105篇
数学   245948篇
物理学   374316篇
  2021年   13607篇
  2020年   16052篇
  2019年   16251篇
  2016年   27869篇
  2015年   20993篇
  2014年   30798篇
  2013年   75110篇
  2012年   40324篇
  2011年   37527篇
  2010年   37334篇
  2009年   39325篇
  2008年   36641篇
  2007年   32073篇
  2006年   39592篇
  2005年   30769篇
  2004年   32116篇
  2003年   30100篇
  2002年   31363篇
  2001年   30316篇
  2000年   26154篇
  1999年   23209篇
  1998年   21463篇
  1997年   21349篇
  1996年   21359篇
  1995年   19392篇
  1994年   18838篇
  1993年   18377篇
  1992年   18504篇
  1991年   18754篇
  1990年   17913篇
  1989年   17942篇
  1988年   17523篇
  1987年   17415篇
  1986年   16411篇
  1985年   22844篇
  1984年   24015篇
  1983年   20156篇
  1982年   21882篇
  1981年   21055篇
  1980年   20387篇
  1979年   20602篇
  1978年   21874篇
  1977年   21455篇
  1976年   21216篇
  1975年   19939篇
  1974年   19637篇
  1973年   20091篇
  1972年   14549篇
  1968年   12355篇
  1967年   12676篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
82.
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   
83.
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   
84.
85.
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   
86.
Translated fromProblemy Ustoichivosti Stokhasticheskikh Modelei. Trudy Seminara, 1988, pp. 84–92.  相似文献   
87.
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   
88.
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   
89.
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   
90.
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   
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