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   10127篇
  免费   888篇
  国内免费   835篇
化学   7718篇
晶体学   108篇
力学   287篇
综合类   66篇
数学   1680篇
物理学   1991篇
  2024年   14篇
  2023年   112篇
  2022年   249篇
  2021年   308篇
  2020年   333篇
  2019年   303篇
  2018年   260篇
  2017年   253篇
  2016年   472篇
  2015年   438篇
  2014年   497篇
  2013年   705篇
  2012年   902篇
  2011年   974篇
  2010年   691篇
  2009年   595篇
  2008年   752篇
  2007年   734篇
  2006年   651篇
  2005年   541篇
  2004年   476篇
  2003年   302篇
  2002年   253篇
  2001年   128篇
  2000年   109篇
  1999年   116篇
  1998年   67篇
  1997年   67篇
  1996年   66篇
  1995年   50篇
  1994年   41篇
  1993年   41篇
  1992年   37篇
  1991年   29篇
  1990年   34篇
  1989年   22篇
  1988年   18篇
  1987年   24篇
  1986年   15篇
  1985年   27篇
  1984年   20篇
  1983年   13篇
  1982年   8篇
  1981年   7篇
  1980年   12篇
  1979年   10篇
  1978年   8篇
  1977年   5篇
  1975年   6篇
  1974年   7篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
951.
In this Letter, the complex dynamical networks with community structure and nonidentical nodes are considered. The globally asymptotical synchronization of the time-delayed complex community networks onto any uniformly smooth state is studied. Some simple and useful criteria are derived by constructing an effective control scheme and adjusting automatically the adaptive coupling strength. Finally, the developed techniques are applied to two complex community networks which are respectively synchronized to a chaotic trajectory and a periodic orbit, and numerical simulations are provided to show the feasibility of the developed methods.  相似文献   
952.
Two new three-step classes of optimal iterative methods to approximate simple roots of nonlinear equations, satisfying the Kung-Traub’s conjecture, are designed. The development of the methods and their convergence analysis are provided joint with a generalization of both processes. In order to check the goodness of the theoretical results, some concrete methods are extracted and numerical and dynamically compared with some known methods.  相似文献   
953.
In this article, by using the stability of Cauchy type integral when the smooth perturbation for integral curve and the Sobolev type perturbation for kernel density happen, we discuss the stability of the second fundamental problem in plane elasticity when the smooth perturbation for the boundary of the elastic domain (unit disk) and the Sobolev type perturbation for the displacement happen. And the error estimate of the displacement between the second fundamental problem and its perturbed problem is obtained.  相似文献   
954.
We study Schauder frames in Fréchet spaces and their duals, as well as perturbation results. We define shrinking and boundedly complete Schauder frames on a locally convex space, study the duality of these two concepts and their relation with the reflexivity of the space. We characterize when an unconditional Schauder frame is shrinking or boundedly complete in terms of properties of the space. Several examples of concrete Schauder frames in function spaces are also presented.  相似文献   
955.
In this paper we establish the existence of mild solutions for a non-autonomous abstract semi-linear second order differential equation submitted to nonlocal initial conditions. Our approach relies on the existence of an evolution operator for the corresponding linear equation and the properties of the Hausdorff measure of non-compactness.  相似文献   
956.
The aim of this work is to obtain the existence of optimal solution and maximum principle for optimal control problem with pointwise type state constraint governed by semilinear parabolic systems with certain polynomial-like nonlinearity. Application to optimal control problems of the phase transition system is given.  相似文献   
957.
In this article, we extend the definition of γ-active constraints for linear semi-infinite programming to a definition applicable to convex semi-infinite programming, by two approaches. The first approach entails the use of the subdifferentials of the convex constraints at a point, while the second approach is based on the linearization of the convex inequality system by means of the convex conjugates of the defining functions. By both these methods, we manage to extend the results on γ-active constraints from the linear case to the convex case.  相似文献   
958.
In coalitional games in which the players are partitioned into groups, we study the incentives of the members of a group to leave it and become singletons. In this context, we model a non-cooperative mechanism in which each player has to decide whether to stay in her group or to exit and act as a singleton. We show that players, acting myopically, always reach a Nash equilibrium.  相似文献   
959.
We consider a random walk in random environment on a strip, which is transient to the right. The random environment is stationary and ergodic. By the constructed enlarged random environment which was first introduced by Goldsheid (2008), we obtain the large deviations conditioned on the environment (in the quenched case) for the hitting times of the random walk.  相似文献   
960.
In this paper, we characterize all the finite dimensional algebras that are derived equivalent to an m?cluster tilted algebra of type $\mathbb{A}$ . These algebras are gentle, and we show that the derived class of such an algebra is completely determined by the rank of its Grothendieck group and the dimension of its first Hochschild cohomology group.  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