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   1421100篇
  免费   25957篇
  国内免费   7833篇
化学   719281篇
晶体学   20681篇
力学   76473篇
综合类   108篇
数学   247214篇
物理学   391133篇
  2021年   13625篇
  2020年   16010篇
  2019年   16166篇
  2018年   15050篇
  2017年   13357篇
  2016年   29103篇
  2015年   21132篇
  2014年   30652篇
  2013年   74698篇
  2012年   42316篇
  2011年   42796篇
  2010年   39750篇
  2009年   41352篇
  2008年   40630篇
  2007年   37251篇
  2006年   40647篇
  2005年   34246篇
  2004年   34372篇
  2003年   31652篇
  2002年   32050篇
  2001年   32609篇
  2000年   27355篇
  1999年   23701篇
  1998年   21496篇
  1997年   21342篇
  1996年   21336篇
  1995年   19352篇
  1994年   18807篇
  1993年   18420篇
  1992年   18879篇
  1991年   19079篇
  1990年   18260篇
  1989年   18264篇
  1988年   17893篇
  1987年   17789篇
  1986年   16752篇
  1985年   23103篇
  1984年   24138篇
  1983年   20212篇
  1982年   21815篇
  1981年   21027篇
  1980年   20367篇
  1979年   20748篇
  1978年   21904篇
  1977年   21544篇
  1976年   21313篇
  1975年   20044篇
  1974年   19700篇
  1973年   20119篇
  1972年   14616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