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   13073篇
  免费   1261篇
  国内免费   960篇
化学   853篇
晶体学   50篇
力学   3134篇
综合类   191篇
数学   8746篇
物理学   2320篇
  2024年   19篇
  2023年   138篇
  2022年   151篇
  2021年   169篇
  2020年   323篇
  2019年   324篇
  2018年   334篇
  2017年   363篇
  2016年   423篇
  2015年   360篇
  2014年   568篇
  2013年   1118篇
  2012年   562篇
  2011年   723篇
  2010年   581篇
  2009年   762篇
  2008年   837篇
  2007年   818篇
  2006年   760篇
  2005年   674篇
  2004年   630篇
  2003年   592篇
  2002年   534篇
  2001年   429篇
  2000年   455篇
  1999年   382篇
  1998年   372篇
  1997年   299篇
  1996年   253篇
  1995年   171篇
  1994年   172篇
  1993年   132篇
  1992年   144篇
  1991年   120篇
  1990年   95篇
  1989年   64篇
  1988年   46篇
  1987年   37篇
  1986年   36篇
  1985年   51篇
  1984年   65篇
  1983年   35篇
  1982年   48篇
  1981年   32篇
  1980年   23篇
  1979年   18篇
  1978年   16篇
  1977年   7篇
  1973年   8篇
  1957年   7篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
This paper is concerned with global stabilization of an undamped non‐linear string in the case where any velocity feedback is not available. The linearized system has an infinite number of poles and zeros on the imaginary axis. In the case where any velocity feedback is not available, a parallel compensator is effective. The stabilizer is constructed for the augmented system which consists of the controlled system and a parallel compensator. It is proved that the string can be stabilized by linear boundary control. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   
72.
This paper is concerned with the standard Lp estimate of solutions to the resolvent problem for the Stokes operator on an infinite layer with ‘Neumann–Dirichlet‐type’ boundary condition. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   
73.
This paper is concerned with well‐posedness results for a mathematical model for the transversal vibrations of a two‐dimensional hybrid elastic structure consisting of a rectangular Reissner–Mindlin plate with a Timoshenko beam attached to its free edge. The model incorporates linear dynamic feedback controls along the interface between the plate and the beam. Classical semigroup methods are employed to show the unique solvability of the coupled initial‐boundary‐value problem. We also show that the energy associated with the system exhibits the property of strong stability. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   
74.
In this article we prove the existence of the solution to the mixed problem for Euler–Bernoulli beam equation with memory term. The existence is proved by means of the Faedo–Galerkin method and the exponential decay is obtained by making use of the multiplier technique combined with integral inequalities due to Komornik. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   
75.
The approximation of solutions to boundary value problems on unbounded domains by those on bounded domains is one of the main applications for artificial boundary conditions. Based on asymptotic analysis, here a new method is presented to construct local artificial boundary conditions for a very general class of elliptic problems where the main asymptotic term is not known explicitly. Existence and uniqueness of approximating solutions are proved together with asymptotically precise error estimates. One class of important examples includes boundary value problems for anisotropic elasticity and piezoelectricity. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   
76.
We study the complex Ginzburg–Landau equation with zero Neumann boundary conditions on a finite interval and establish that this boundary problem (with suitably chosen parameters) has countably many stable two-dimensional self-similar tori. The case of periodic boundary conditions is also investigated.  相似文献   
77.
一类具有非局部反应扩散方程的奇摄动问题   总被引:7,自引:0,他引:7  
莫嘉琪 《数学进展》1998,27(1):53-58
本文讨论一类具非局部反应扩散方程的奇摄动初始边值问题,利用迭代法及微分不等式,研究了初始边值问题的存在唯一及其渐近性态。  相似文献   
78.
1.IntroductionTheoptimalityconditionsofmathematicalprogrammingisaveryimportantsubjectbecausetLeyprovideausefulanalyticaltoolforstudingthedualitytheoryandnonlinearprogrammingalgoirthms.Inrecelltyears,someauthorshavebeguntostudytheoptimalityconditionsforvectoroptimizationproblemofset-valuedmapping,suchas[4][51.Inthispaperlwedefinetheconceptofcone--weaklyefficientsubdifferentialofset-valuedmappinginthecaseofgeneralpartiallyorderedlocallyconvextopologicalvectorspaces.Thecone-weaklysubdifferential…  相似文献   
79.
We consider initial boundary value problems for the equations of the one-dimensional motion of a viscous, heat-conducting gas with density-dependent viscosity that decreases (to zero) with decreasing density. We prove that if the viscosity does not decrease to zero too rapidly, then smooth solutions exist globally in time.  相似文献   
80.
The purpose of this paper is to give the Reid ``Roundabout Theorem' for quadratic functionals with general boundary conditions. In particular, we describe the so-called coupled point and regularity condition introduced in [16] in terms of Riccati equation solutions. Accepted 27 February 1996  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