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   1430253篇
  免费   26170篇
  国内免费   7874篇
化学   719568篇
晶体学   21068篇
力学   77302篇
综合类   111篇
数学   250242篇
物理学   396006篇
  2021年   13674篇
  2020年   16067篇
  2019年   16244篇
  2018年   16796篇
  2017年   15433篇
  2016年   29866篇
  2015年   21393篇
  2014年   30746篇
  2013年   74878篇
  2012年   42665篇
  2011年   44250篇
  2010年   41128篇
  2009年   42879篇
  2008年   42130篇
  2007年   39148篇
  2006年   40032篇
  2005年   35528篇
  2004年   34697篇
  2003年   31761篇
  2002年   31816篇
  2001年   31581篇
  2000年   26679篇
  1999年   23437篇
  1998年   21404篇
  1997年   21272篇
  1996年   21318篇
  1995年   19324篇
  1994年   18820篇
  1993年   18406篇
  1992年   18708篇
  1991年   18903篇
  1990年   18120篇
  1989年   18160篇
  1988年   17744篇
  1987年   17683篇
  1986年   16598篇
  1985年   22972篇
  1984年   24056篇
  1983年   20161篇
  1982年   21777篇
  1981年   21013篇
  1980年   20325篇
  1979年   20685篇
  1978年   21879篇
  1977年   21502篇
  1976年   21201篇
  1975年   19910篇
  1974年   19568篇
  1973年   19985篇
  1972年   14475篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
81.
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   
82.
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   
83.
84.
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   
85.
Translated fromProblemy Ustoichivosti Stokhasticheskikh Modelei. Trudy Seminara, 1988, pp. 84–92.  相似文献   
86.
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   
87.
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   
88.
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   
89.
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   
90.
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