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   3208篇
  免费   296篇
  国内免费   363篇
化学   482篇
晶体学   5篇
力学   100篇
综合类   117篇
数学   2563篇
物理学   600篇
  2024年   2篇
  2023年   19篇
  2022年   37篇
  2021年   58篇
  2020年   79篇
  2019年   76篇
  2018年   93篇
  2017年   86篇
  2016年   104篇
  2015年   74篇
  2014年   159篇
  2013年   284篇
  2012年   148篇
  2011年   207篇
  2010年   177篇
  2009年   229篇
  2008年   246篇
  2007年   228篇
  2006年   196篇
  2005年   169篇
  2004年   177篇
  2003年   159篇
  2002年   145篇
  2001年   104篇
  2000年   81篇
  1999年   99篇
  1998年   86篇
  1997年   74篇
  1996年   46篇
  1995年   37篇
  1994年   34篇
  1993年   18篇
  1992年   21篇
  1991年   13篇
  1990年   19篇
  1989年   15篇
  1988年   12篇
  1987年   6篇
  1986年   7篇
  1985年   6篇
  1984年   8篇
  1983年   7篇
  1982年   3篇
  1981年   5篇
  1980年   2篇
  1979年   3篇
  1977年   2篇
  1974年   2篇
  1959年   1篇
  1936年   2篇
排序方式: 共有3867条查询结果,搜索用时 31 毫秒
991.
Given f:X→R∪{+∞}f:XR{+} a convex and lower semi-continuous function defined on a reflexive Banach space X, and L, a closed linear manifold of X over which f takes at least a real value, the aim of this note is to prove the following Baire category result: in the Euclidean setting, the set of affine functions dominated by f on L for which there is no dominated extension to X is always of first Baire category, but this set can be as large as a residual set, provided that X is a reflexive Banach space of infinite dimension.  相似文献   
992.
993.
石忠锐  张博 《数学杂志》2014,34(3):406-416
本文研究了赋Luxemburg范数广义Orlicz序列空间的(J)非方点.通过分析、综合经典Orlicz空间与广义Orlicz空间的结构,给出了用生成函数表达该性质的充分必要条件.该结果不仅推广了经典空间的结果,也是十分好用的.  相似文献   
994.
This paper is concerned with the linear ODE in the form y′(t) = λρ(t)y(t) + b(t), λ < 0 which represents a simplified storage model of the carbon in the soil. In the first part, we show that, for a periodic function ρ(t), a linear drift in the coefficient b(t) involves a linear drift for the solution of this ODE. In the second part, we extend the previous results to a classical heat non-homogeneous equation. The connection with an analytic semi-group associated to the ODE equation is considered in the third part. Numerical examples are given.  相似文献   
995.
Abstract

In this article, we study Δ-convergence of iterations for a sequence of strongly quasi-nonexpansive mappings as well as the strong convergence of the Halpern type regularization of them in Hadamard spaces. Then, we give some their applications to iterative methods, convex and pseudo-convex minimization (proximal point algorithm), fixed point theory and equilibrium problems. The results extend several new results in the literature and some of them seem new even in Hilbert spaces. One of our motivations is to unify some usual iterative methods in fixed point theory and proximal methods using the iterations generated by a sequence of strongly nonexpansive mappings.  相似文献   
996.
997.
In this paper,we are concerned with the regularity and symmetry of positive solutions of the following nonlinear integral system u(x) = ∫R n G α(x-y)v(y) q/|y|β dy,v(x) = ∫R n G α(x-y)u(y) p/|y|β dy for x ∈ R n,where G α(x) is the kernel of Bessel potential of order α,0 ≤β < α < n,1 < p,q < n-β/β and 1/p + 1 + 1/q + 1 > n-α + β/n.We show that positive solution pairs(u,v) ∈ L p +1(R n) × L q +1(R n) are Ho¨lder continuous,radially symmetric and strictly decreasing about the origin.  相似文献   
998.
徐怀 《数学杂志》2012,32(3):388-394
本文研究了宽平稳序列具有均方遍历性的充要条件问题.利用施瓦兹不等式,获得了复宽平稳序列均方遍历性的两个充要条件和一个易于验证的充分条件.  相似文献   
999.
《Optimization》2012,61(7):997-1011
In this article, the concepts of well-posedness and well-posedness in the generalized sense are introduced for parametric quasivariational inequality problems with set-valued maps. Metric characterizations of well-posedness and well-posedness in the generalized sense, in terms of the approximate solutions sets, are presented. Characterization of well-posedness under certain compactness assumptions and sufficient conditions for generalized well-posedness in terms of boundedness of approximate solutions sets are derived. The study is further extended to discuss well-posedness for an optimization problem with quasivariational inequality constraints.  相似文献   
1000.
An n‐tuple π (not necessarily monotone) is graphic if there is a simple graph G with vertex set {v1, …, vn} in which the degree of vi is the ith entry of π. Graphic n‐tuples (d, …, d) and (d, …, d) pack if there are edge‐disjoint n‐vertex graphs G1 and G2 such that d(vi) = d and d(vi) = d for all i. We prove that graphic n‐tuples π1 and π2 pack if , where Δand δdenote the largest and smallest entries in π1 + π2 (strict inequality when δ = 1); also, the bound is sharp. Kundu and Lovász independently proved that a graphic n‐tuple π is realized by a graph with a k‐factor if the n‐tuple obtained by subtracting k from each entry of π is graphic; for even n we conjecture that in fact some realization has k edge‐disjoint 1‐factors. We prove the conjecture in the case where the largest entry of π is at most n/2 + 1 and also when k?3. © 2011 Wiley Periodicals, Inc. J Graph Theory  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