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   1391951篇
  免费   25914篇
  国内免费   7764篇
化学   699276篇
晶体学   20522篇
力学   75657篇
综合类   107篇
数学   244587篇
物理学   385480篇
  2021年   13575篇
  2020年   15953篇
  2019年   16097篇
  2018年   14177篇
  2016年   28712篇
  2015年   20955篇
  2014年   30565篇
  2013年   74576篇
  2012年   40719篇
  2011年   39742篇
  2010年   38603篇
  2009年   40611篇
  2008年   38109篇
  2007年   34495篇
  2006年   38845篇
  2005年   31932篇
  2004年   32613篇
  2003年   30151篇
  2002年   30866篇
  2001年   31498篇
  2000年   26558篇
  1999年   23310篇
  1998年   21362篇
  1997年   21314篇
  1996年   21232篇
  1995年   19261篇
  1994年   18726篇
  1993年   18274篇
  1992年   18612篇
  1991年   18847篇
  1990年   18021篇
  1989年   18069篇
  1988年   17592篇
  1987年   17570篇
  1986年   16578篇
  1985年   22917篇
  1984年   24046篇
  1983年   20164篇
  1982年   21767篇
  1981年   20997篇
  1980年   20327篇
  1979年   20660篇
  1978年   21863篇
  1977年   21496篇
  1976年   21244篇
  1975年   19940篇
  1974年   19584篇
  1973年   20061篇
  1972年   14521篇
  1967年   12734篇
排序方式: 共有10000条查询结果,搜索用时 15 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