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   1611470篇
  免费   32314篇
  国内免费   8518篇
化学   720203篇
晶体学   20544篇
力学   76193篇
综合类   108篇
数学   246702篇
物理学   389042篇
无线电   199510篇
  2021年   14942篇
  2020年   17519篇
  2019年   17684篇
  2018年   15575篇
  2017年   13651篇
  2016年   30918篇
  2015年   22136篇
  2014年   33089篇
  2013年   79105篇
  2012年   44805篇
  2011年   45038篇
  2010年   42371篇
  2009年   46489篇
  2008年   46873篇
  2007年   44769篇
  2006年   49289篇
  2005年   42278篇
  2004年   42448篇
  2003年   39086篇
  2002年   39430篇
  2001年   39921篇
  2000年   34338篇
  1999年   30276篇
  1998年   27978篇
  1997年   27717篇
  1996年   27160篇
  1995年   24872篇
  1994年   24372篇
  1993年   23785篇
  1992年   24057篇
  1991年   24174篇
  1990年   22939篇
  1989年   22539篇
  1988年   21722篇
  1987年   20394篇
  1986年   19266篇
  1985年   25678篇
  1984年   26686篇
  1983年   22503篇
  1982年   23836篇
  1981年   23018篇
  1980年   22257篇
  1979年   22373篇
  1978年   23512篇
  1977年   23095篇
  1976年   22767篇
  1975年   21444篇
  1974年   21087篇
  1973年   21570篇
  1972年   15721篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
971.
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   
972.
Two‐dimensional arrangements of molecules can show remarkable cooperative electronic effects. Such effects can serve to achieve direct electronic sensing of chemical and physical processes via electrostatic effects, i.e., without transfer of charge or matter between the locus of sensing and that of detection.  相似文献   
973.
Haug  K. Maloberti  F. Temes  G.C. 《Electronics letters》1985,21(24):1156-1157
Compensated SC integrator stages are analysed and compared with respect to their sensitivities to finite amplifier gain effects. Simple single-stage amplifiers may be used in such circuits even in highly selective filtering applications. This may allow an extension of the present frequency range of SC circuits.  相似文献   
974.
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   
975.
976.
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   
977.
Translated fromProblemy Ustoichivosti Stokhasticheskikh Modelei. Trudy Seminara, 1988, pp. 84–92.  相似文献   
978.
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   
979.
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   
980.
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