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   795篇
  免费   25篇
  国内免费   65篇
化学   4篇
晶体学   1篇
力学   19篇
综合类   11篇
数学   825篇
物理学   25篇
  2023年   4篇
  2022年   4篇
  2021年   5篇
  2020年   5篇
  2019年   24篇
  2018年   13篇
  2017年   16篇
  2016年   14篇
  2015年   15篇
  2014年   20篇
  2013年   50篇
  2012年   45篇
  2011年   34篇
  2010年   29篇
  2009年   49篇
  2008年   40篇
  2007年   50篇
  2006年   42篇
  2005年   34篇
  2004年   32篇
  2003年   29篇
  2002年   30篇
  2001年   41篇
  2000年   35篇
  1999年   27篇
  1998年   23篇
  1997年   30篇
  1996年   20篇
  1995年   16篇
  1994年   16篇
  1993年   12篇
  1992年   9篇
  1991年   7篇
  1990年   5篇
  1988年   5篇
  1987年   8篇
  1986年   3篇
  1985年   4篇
  1984年   3篇
  1983年   3篇
  1982年   8篇
  1981年   6篇
  1980年   4篇
  1979年   4篇
  1978年   1篇
  1977年   3篇
  1976年   5篇
  1974年   2篇
  1971年   1篇
排序方式: 共有885条查询结果,搜索用时 15 毫秒
1.
在局部凸空间已有的中点局部kk-一致凸性和中点局部k-一致光滑性这一对对偶概念的基础上,证明了中点局部kk-一致凸性与中点局部(k+1)-一致凸性的关系,给出了在P-自反的条件下它们之间的等价对偶定理.  相似文献   
2.
Toll convexity is a variation of the so-called interval convexity. A tolled walk T between two non-adjacent vertices u and v in a graph G is a walk, in which u is adjacent only to the second vertex of T and v is adjacent only to the second-to-last vertex of T. A toll interval between u,vV(G) is a set TG(u,v)={xV(G):x lies on a tolled walk between u and v}. A set S?V(G) is toll convex, if TG(u,v)?S for all u,vS. A toll closure of a set S?V(G) is the union of toll intervals between all pairs of vertices from S. The size of a smallest set S whose toll closure is the whole vertex set is called a toll number of a graph G, tn(G). The first part of the paper reinvestigates the characterization of convex sets in the Cartesian product of two graphs. It is proved that the toll number of the Cartesian product of two graphs equals 2. In the second part, the toll number of the lexicographic product of two graphs is studied. It is shown that if H is not isomorphic to a complete graph, tn(G°H)3?tn(G). We give some necessary and sufficient conditions for tn(G°H)=3?tn(G). Moreover, if G has at least two extreme vertices, a complete characterization is given. Furthermore, graphs with tn(G°H)=2 are characterized. Finally, the formula for tn(G°H) is given — it is described in terms of the so-called toll-dominating triples or, if H is complete, toll-dominating pairs.  相似文献   
3.
《Mathematische Nachrichten》2017,290(17-18):3020-3028
Let X be a measurable space, let be a family of measurable subsets of it, and let be a subspace of complex measures on X that is also closed under restrictions of measures. In this paper we introduce the ‐convergence topology and the ‐strict topology on . Among other results, we find necessary and sufficient conditions for Hausdorff‐ness and coincide‐ness of these topologies. Applications to Lebesgue spaces, and also examples in Hausdorff topological spaces and locally compact groups are given.  相似文献   
4.
This paper is concerned with Hölder continuity of the solution to a saddle point problem. Some new su?cient conditions for the uniqueness and Hölder continuity of the solution for a perturbed saddle point problem are established. Applications of the result on Hölder continuity of the solution for perturbed constrained optimization problems are presented under mild conditions. Examples are given to illustrate the obtained results.  相似文献   
5.
6.
We study nonlinear orbital stability and instability of the set of ground state solitary wave solutions of a one-dimensional Boussinesq equation or one-dimensional Benney–Luke equation. It is shown that a solitary wave (traveling wave with finite energy) may be orbitally stable or unstable depending on the range of the wave's speed of propagation.  相似文献   
7.
CHARACTERISTICSOFSUBDIFFERENTIALSOFFUNCTIONS(郭兴明)CHARACTERISTICSOFSUBDIFFERENTIALSOFFUNCTIONS¥GuoXingming(ReceivedJune16,1995...  相似文献   
8.
We show that a planar BV homeomorphism can be approximated in the area strict sense, together with its inverse, with smooth or piecewise affine homeomorphisms.  相似文献   
9.
The paper considers a statistical concept of causality in continuous time in the filtered probability spaces which is based on the Granger’s definition of causality. The given causality concept is then applied to the solution of the martingale problem (associated with the stochastic differential equation driven with semimartingales). More precisely, we show that the given causality concept is closely connected to the concept of extremality of measures for the solutions of the martingale problem, for the stopped martingale problem and for the local martingale problem. We also show the equivalence between some models of causality and local uniqueness (for the solutions of the martingale problem).  相似文献   
10.
In this paper we investigate spectral matrices, i.e., matrices with equal spectral and numerical radii. Various characterizations and properties of these matrices are given.  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