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   2934篇
  免费   49篇
  国内免费   11篇
化学   1773篇
晶体学   60篇
力学   96篇
数学   278篇
物理学   787篇
  2023年   25篇
  2022年   31篇
  2021年   21篇
  2020年   30篇
  2019年   39篇
  2018年   28篇
  2017年   33篇
  2016年   66篇
  2015年   44篇
  2014年   68篇
  2013年   164篇
  2012年   134篇
  2011年   222篇
  2010年   147篇
  2009年   137篇
  2008年   160篇
  2007年   209篇
  2006年   156篇
  2005年   126篇
  2004年   103篇
  2003年   103篇
  2002年   68篇
  2001年   31篇
  2000年   36篇
  1999年   38篇
  1998年   29篇
  1997年   29篇
  1996年   29篇
  1995年   28篇
  1994年   23篇
  1993年   24篇
  1992年   28篇
  1991年   22篇
  1990年   31篇
  1989年   19篇
  1987年   28篇
  1986年   29篇
  1985年   30篇
  1984年   25篇
  1983年   19篇
  1982年   31篇
  1981年   36篇
  1980年   22篇
  1979年   33篇
  1978年   27篇
  1976年   22篇
  1975年   21篇
  1974年   19篇
  1973年   20篇
  1972年   18篇
排序方式: 共有2994条查询结果,搜索用时 15 毫秒
121.
We will show that an uniform treatment yields Wiener–Tauberian type results for various Banach algebras and modules consisting of radial sections of some homogenous vector bundles on rank one Riemannian symmetric spaces G/K of noncompact type. One example of such a vector bundle is the spinor bundle. The algebras and modules we consider are natural generalizations of the commutative Banach algebra of integrable radial functions on G/K. The first set of them are Beurling algebras with analytic weights, while the second set arises due to Kunze–Stein phenomenon for noncompact semisimple Lie groups.  相似文献   
122.
The problem of defining threat strategies in nonzero-sum games is considered, and a definition of optimal threat strategies is proposed in the static case. This definition is then extended to differential games, and sufficient conditions for optimality of threat strategies are derived. These are then applied to a simple example. The definition proposed here is then compared with the definition of threat strategies given by Nash.  相似文献   
123.
The present paper outlines some basic principles upon which an outlook in teaching and research in mathematics in educational institutions can be developed. Defining applied mathematics, the author analyses the basic topics of mathematics which permeate throughout the wider fields and diversified aspects of this branch of mathematical science.

For the institutions of learning, a course curriculum has been proposed which will gradually motivate, orient and prepare individuals through the process of learning to understand the methods and techniques, so as to apply them to physical problems. This has been illustrated in the fields of fluid dynamics and aerodynamics through the analysis of complex function theory and differential equations.

Because of the frustrating situations prevailing amongst students and teachers in the institutions of learning in the present day, a critical analysis has been made to identify the respective roles of the academicians and administrators, and with a view to improving the situation, some remedy has been suggested regarding teaching and research in educational institutions.  相似文献   
124.
The object of the present investigation is to introduce a new trigonometric method of summation which is both regular and Fourier effective and determine its status with reference to other methods of summation (see §2-§4) and also give an application of this method to determine the degree of approximation in a new Banach space of functions conceived as a generalized Holder metric (see §5).  相似文献   
125.
The current article devoted on the new method for finding the exact solutions of some time‐fractional Korteweg–de Vries (KdV) type equations appearing in shallow water waves. We employ the new method here for time‐fractional equations viz. time‐fractional KdV‐Burgers and KdV‐mKdV equations for finding the exact solutions. We use here the fractional complex transform accompanied by properties of local fractional calculus for reduction of fractional partial differential equations to ordinary differential equations. The obtained results are demonstrated by graphs for the new solutions. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   
126.
In this paper, numerical solutions of fractional Fokker–Planck equations with Riesz space fractional derivatives have been developed. Here, the fractional Fokker–Planck equations have been considered in a finite domain. In order to deal with the Riesz fractional derivative operator, shifted Grünwald approximation and fractional centred difference approaches have been used. The explicit finite difference method and Crank–Nicolson implicit method have been applied to obtain the numerical solutions of fractional diffusion equation and fractional Fokker–Planck equations, respectively. Numerical results are presented to demonstrate the accuracy and effectiveness of the proposed numerical solution techniques. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   
127.
In this paper, we consider the problem of robust stability of a class of linear uncertain neutral systems with interval time-varying delay under (i) nonlinear perturbations in state, and (ii) time-varying parametric uncertainties using Lyapunov-Krasovskii approach. By constructing a candidate Lyapunov-Krasovskii (LK) functional, that takes into account the delay-range information appropriately, less conservative robust stability criteria are proposed in terms of linear matrix inequalities (LMI) to compute the maximum allowable bound for the delay-range within which the uncertain neutral system under consideration remains asymptotically stable. The reduction in conservatism of the proposed stability criterion over recently reported results is attributed to the fact that time-derivative of the LK functional is bounded tightly without neglecting any useful terms using a minimal number of slack matrix variables. The analysis, subsequently, yields a stability condition in convex LMI framework, that can be solved non-conservatively at boundary conditions using standard LMI solvers. The effectiveness of the proposed stability criterion is demonstrated through standard numerical examples.  相似文献   
128.
Roger Bustamante  Luis Dorfmann  Ray W. Ogden 《PAMM》2007,7(1):1090703-1090704
This paper focuses on a variational formulation for a magneto-active elastomer completely surrounded by free space. The free space is considered infinite, with an applied magnetic field or magnetic induction vector as the far field boundary conditions. In addition to the effect of the Maxwell stress exterior to the body on its surface, a mechanical load is applied over a portion of the surface, but no displacement constraints are considered. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   
129.
Widely publicized reports of fresh MBAs getting multiple job offers with six-figure annual salaries leave a long-lasting general impression about the high quality of selected business schools. While such spectacular achievement in job placement rightly deserves recognition, one should not lose sight of the resources expended in order to accomplish this result. In this study, we employ a measure of Pareto-Koopmans global efficiency to evaluate the efficiency levels of the MBA programs in Business Week’s top-rated list. We compute input- and output-oriented radial and non-radial efficiency measures for comparison. Among three tier groups, the schools from a higher tier group on average are more efficient than those from lower tiers, although variations in efficiency levels do occur within the same tier, which exist over different measures of efficiency.  相似文献   
130.
A model of collective bargaining in differential games, similar to one considered by Leitmann (Ref. 1), is proposed. Optimal threat strategies are then found and compared with Leitmann's solution. Nash-optimal threat strategies are also found and compared with the other two solutions.The author would like to thank Professor G. Leitmann of the University of California for bringing the author's attention to this subject.  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