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   9075篇
  免费   410篇
  国内免费   379篇
化学   408篇
晶体学   5篇
力学   394篇
综合类   102篇
数学   8394篇
物理学   561篇
  2023年   43篇
  2022年   88篇
  2021年   94篇
  2020年   106篇
  2019年   118篇
  2018年   132篇
  2017年   171篇
  2016年   184篇
  2015年   131篇
  2014年   378篇
  2013年   489篇
  2012年   510篇
  2011年   399篇
  2010年   393篇
  2009年   554篇
  2008年   578篇
  2007年   629篇
  2006年   457篇
  2005年   387篇
  2004年   312篇
  2003年   329篇
  2002年   302篇
  2001年   268篇
  2000年   272篇
  1999年   233篇
  1998年   206篇
  1997年   189篇
  1996年   213篇
  1995年   186篇
  1994年   136篇
  1993年   141篇
  1992年   140篇
  1991年   134篇
  1990年   103篇
  1989年   71篇
  1988年   94篇
  1987年   54篇
  1986年   84篇
  1985年   119篇
  1984年   80篇
  1983年   23篇
  1982年   55篇
  1981年   44篇
  1980年   35篇
  1979年   31篇
  1978年   51篇
  1977年   49篇
  1976年   27篇
  1975年   12篇
  1974年   13篇
排序方式: 共有9864条查询结果,搜索用时 0 毫秒
1.
Murty's algorithm for the linear complementarity problem is generalized to solve the optimality conditions for linear and convex quadratic programming problems with both equality and inequality constraints. An implementation is suggested which provides both efficiency and tight error control. Numerical experiments as well as field tests in various applications show favorable results.The author thanks K. G. Murty for his encouragement and helpful comments.  相似文献   
2.
谢胜利 《大学数学》2002,18(3):9-12
本文定义了二阶微分方程的弱 Carathéodory解 ,在不涉及紧型条件的情形下 ,直接用迭代法证明了 Banach空间二阶非线性常微分方程两点边值问题存在唯一解 ,并给出逼近解迭代序列的误差估计 ,对周期边值问题得到类似的结果  相似文献   
3.
The method of equivalent variational methods, originally due to Carathéodory for free problems in the calculus of variations is extended to investigate feedback Nash equilibria for a class of n-person differential games. Both the finite-horizon and infinite-horizon cases are considered. Examples are given to illustrate the presented results.  相似文献   
4.
We consider applications of disjunctive programming to global optimization and problems with equilibrium constraints. We propose a modification of the algorithm of F. Beaumont for disjunctive programming problems and show its numerical efficiency.  相似文献   
5.
We consider the problem of maximizing a linear fractional function on the Pareto efficient frontier of two other linear fractional functions. We present a finite pivoting-type algorithm that solves the maximization problem while computing simultaneously the efficient frontier. Application to multistage efficiency analysis is discussed. An example demonstrating the computational procedure is included.  相似文献   
6.
This paper relates the author's personal experience with constraint programming and gives a personal assessment of the relationships between constraint programming and operations research.  相似文献   
7.
线性分式规划最优解集的求法   总被引:5,自引:0,他引:5  
本文使用多面集的表示定理,导出了线性分式规划最优解集的结构,并给出确定全部最优解的计算步骤。  相似文献   
8.
This paper deals with mathematical human resource planning; more specifically, it suggests a new model for a manpower‐planning system. In general, we study a k‐classed hierarchical system where the workforce demand at each time period is satisfied through internal mobility and recruitment. The motivation for this work is based on various European Union incentives, which promote regional or local government assistance programs that could be exploited by firms not only for hiring and training newcomers, but also to improve the skills and knowledge of their existing personnel. In this respect, in our augmented mobility model we establish a new ‘training/standby’ class, which serves as a manpower inventory position for potential recruits. This class, which may very well be internal or external to the system, is incorporated into the framework of a non‐homogeneous Markov chain model. Furthermore, cost objectives are employed using the goal‐programming approach, under different operating assumptions, in order to minimize the operational cost in the presence of system's constraints and regulations. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   
9.
Toward Fuzzy Optimization without Mathematical Ambiguity   总被引:15,自引:0,他引:15  
Fuzzy programming has been discussed widely in literature and applied in such various disciplines as operations research, economic management, business administration, and engineering. The main purpose of this paper is to present a brief review on fuzzy programming models, and classify them into three broad classes: expected value model, chance-constrained programming and dependent-chance programming. In order to solve general fuzzy programming models, a hybrid intelligent algorithm is also documented. Finally, some related topics are discussed.  相似文献   
10.
非线性奇异边值问题的正解   总被引:1,自引:0,他引:1  
利用锥映射的不动点指数定量,研究了一类非线性奇异边值问题多个正解的存在性问题。在构造的解的存在条件之下,证明了奇异边值问题至少有两个正解的存在性定理。  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