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   4366篇
  免费   217篇
  国内免费   400篇
化学   234篇
晶体学   3篇
力学   68篇
综合类   38篇
数学   2431篇
物理学   194篇
综合类   2015篇
  2024年   7篇
  2023年   36篇
  2022年   38篇
  2021年   44篇
  2020年   58篇
  2019年   82篇
  2018年   85篇
  2017年   81篇
  2016年   86篇
  2015年   88篇
  2014年   184篇
  2013年   233篇
  2012年   192篇
  2011年   203篇
  2010年   208篇
  2009年   259篇
  2008年   317篇
  2007年   298篇
  2006年   290篇
  2005年   259篇
  2004年   202篇
  2003年   202篇
  2002年   162篇
  2001年   177篇
  2000年   155篇
  1999年   147篇
  1998年   128篇
  1997年   108篇
  1996年   116篇
  1995年   69篇
  1994年   63篇
  1993年   58篇
  1992年   45篇
  1991年   35篇
  1990年   35篇
  1989年   44篇
  1988年   24篇
  1987年   20篇
  1986年   10篇
  1985年   26篇
  1984年   18篇
  1983年   4篇
  1982年   14篇
  1981年   16篇
  1980年   19篇
  1979年   15篇
  1978年   9篇
  1977年   5篇
  1976年   4篇
  1936年   1篇
排序方式: 共有4983条查询结果,搜索用时 15 毫秒
41.
We give an estimate for the number of elements in the intersection of topological Sidon sets inR n with compact convex subsets and deduce a necessary and sufficient conditions for an orbit of a linear transformation ofR n to be a topological Sidon set.  相似文献   
42.
Fixed Point Theorems on Product Topological Spaces and Applications   总被引:3,自引:0,他引:3  
A new collectively fixed point theorem for a family of set-valued mappings defined on product spaces of non-compact topological spaces without linear structure is proved and some special cases are also discussed. As applications, some non-empty intersection theorems of sets with convex sections and equilibrium existence theorem of abstract economies are obtained under much weaker assumptions. Our results includes a number of known results as many special cases.  相似文献   
43.
粗可能性测度   总被引:1,自引:1,他引:0  
给定模糊可测空间(X,A)及(X,A)上的可能性测度,通过应用粗集理论,将可能性测度Ⅱ和模糊糊积分分别扩充至P(X)和F(X)上,从而引入粗可能性测度的概念。  相似文献   
44.
Goguadze  D. F. 《Mathematical Notes》2003,74(3-4):346-351
We introduce a generalized notion of semiring and prove that all known properties that semirings have according to the old definition are preserved.  相似文献   
45.
在L-smooth拓扑空间中借助于L-smooth半闭集给出了L-smooth s-远域、s-附着点、s-聚点等概念,进一步讨论了网的s收-敛,并研究了它们的一些基本性质.从而,丰富了已有的结果.  相似文献   
46.
In finite dimensional Euclidean space, we prove the contractibility of the efficient frontier of simply shaded sets. This work extends the result of Peleg [7], which confirms the contractibility of the efficient frontier in the convex case.  相似文献   
47.
Noninferior Nash Strategies for Multi-Team Systems   总被引:1,自引:0,他引:1  
This paper is concerned with the optimization of systems that are controlled by several teams of decision makers. The decision makers within each team cooperate for the benefit of their team. On the other hand, the teams compete among themselves in order to achieve an objective that relates to the overall performance of the system. An approach that merges concepts from team theory and game theory for dealing with such systems and a solution called the noninferior Nash strategy are introduced. This multi-team solution provides a new framework for analyzing hierarchically controlled systems so as to address complicated coordination problems among the decision makers. The properties of the noninferior Nash solution in static multi-team systems are investigated and necessary conditions for its existence are derived. Analytical expressions for the noninferior Nash strategies are derived for a class of linear-quadratic static multi-team games. In order to deal with the issue of nonuniqueness of the solution, the concept of a noninferior Nash strategy with a team leader is introduced. Several examples are presented to illustrate the results.  相似文献   
48.
For the Queens_n 2 graph coloring problems no chromatic numbers are available for n > 9 except where n is not a multiple of 2 or 3. In this paper we propose an exact algorithm that takes advantage of the particular structure of these graphs. The algorithm works on the independent sets of the graph rather than on the vertices to be colored. It combines branch and bound, for independent set assignment, with a clique based filtering procedure. A first experimentation of this approach provided the coloring number values ranging for n = 10 to n = 14.  相似文献   
49.
In this paper, we suggest and analyze some iterative methods for solving nonconvex variational inequalities using the auxiliary principle technique, the convergence of which requires either only pseudomonotonicity or partially relaxed strong monotonicity. Our proofs of convergence are very simple. As special cases, we obtain earlier results for solving general variational inequalities involving convex sets.  相似文献   
50.
A linear inequality system with infinitely many constraints is polynomial (analytical) if its index set is a compact interval of the real line and all its coefficients are polynomial (analytical, respectively) functions of the index on this interval. This paper provides an example of analytical system whose solution set cannot be the solution set of any polynomial system. Research supported by DGES of Spain and FEDER of UE, Grant BFM2002-04114-C02-01. Research supported by CONACyT of Mexico, Grant 130036. Research partially supported by CONACyT of Mexico, Grant 44003.  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