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   4494篇
  免费   372篇
  国内免费   334篇
化学   366篇
晶体学   18篇
力学   794篇
综合类   65篇
数学   2672篇
物理学   1285篇
  2024年   20篇
  2023年   50篇
  2022年   88篇
  2021年   98篇
  2020年   124篇
  2019年   119篇
  2018年   141篇
  2017年   117篇
  2016年   134篇
  2015年   127篇
  2014年   217篇
  2013年   316篇
  2012年   183篇
  2011年   237篇
  2010年   218篇
  2009年   246篇
  2008年   243篇
  2007年   258篇
  2006年   260篇
  2005年   215篇
  2004年   164篇
  2003年   200篇
  2002年   164篇
  2001年   135篇
  2000年   132篇
  1999年   130篇
  1998年   86篇
  1997年   107篇
  1996年   71篇
  1995年   71篇
  1994年   60篇
  1993年   59篇
  1992年   58篇
  1991年   61篇
  1990年   37篇
  1989年   24篇
  1988年   22篇
  1987年   22篇
  1986年   18篇
  1985年   22篇
  1984年   24篇
  1983年   10篇
  1982年   21篇
  1981年   12篇
  1980年   17篇
  1979年   17篇
  1978年   6篇
  1977年   9篇
  1976年   12篇
  1974年   6篇
排序方式: 共有5200条查询结果,搜索用时 15 毫秒
11.
In this paper, the authors obtain sharp upper and lower hounds for the heat kernel associated with Jacobi transform, and get some analogues of Hardy‘s Theorem for Jacobi transform by using the sharp estimate of the heat kernel.  相似文献   
12.
A nonnegative 1-periodic multifractal measure on is obtained as infinite random product of harmonics of a 1-periodic function W(t). Such infinite products are statistically self-affine and generalize certain Riesz products with random phases. They are martingale structures, therefore converge. The criterion on W for nondegeneracy is provided. It differs completely from those for other known random measures constructed as martingale limits of multiplicative processes. In particular, it is very sensitive to small changes in W(t). When these infinite products are interpreted in the framework of thermodynamic formalism for random transformations, logW is a potential function when W>0. For regular enough potentials, in case of degeneracy, the natural normalization makes the sequence of measures converge. Moreover, this normalization is neutral for nondegenerate martingales. The multifractal analysis of the limit martingale measure is performed for a class of potential functions having a dense countable set of jump points.  相似文献   
13.
In this paper, we extend the Hölderian invariance principle of Lamperti [6] to the case of partial-sum processes based on a triangular array of row-wise independent random variables. As an application, we obtain necessary and sufficient conditions for the almost sure (resp. in probability) weak Hölder convergence of partial-sum processes based on bootstrapped samples.  相似文献   
14.
本文利用比较原理以及一种特殊变换研究了一类非线性退化方程的混合问题,得到了这类复杂问题解的渐进性质。  相似文献   
15.
On the Application of the Auxiliary Problem Principle   总被引:6,自引:0,他引:6  
The auxiliary problem principle (APP) derives from a general theory on decomposition-coordination methods establishing a comprehensive framework for both one-level and two-level methods. In this paper, the results of the two-level methods of APP are specialized for an efficient application to some engineering problems.  相似文献   
16.
In this paper, a generalized anti–maximum principle for the second order differential operator with potentials is proved. As an application, we will give a monotone iterative scheme for periodic solutions of nonlinear second order equations. Such a scheme involves the Lp norms of the growth, 1 ≤ p ≤ ∞, while the usual one is just the case p = ∞.  相似文献   
17.
The authors establish the Hilbertian invariance principle for the empirical process of a stationary Markov process, by extending the forward-backward martingale decomposition of Lyons-Meyer-Zheng to the Hilbert space valued additive functionals associated with general non-reversible Markov processes.  相似文献   
18.
本文给出了如下形式的p(x)-Laplace方程 -div(|u|~(p(x)-2)u)+d(x)|u|~q(x)-2)u=0,x∈Ω的一个强极大值原理,其中p(x),q(x),d(x)满足一定的条件。  相似文献   
19.
This paper is concerned with the maximum principle for second-order linear elliptic equations in a wide generality. By means of a geometric condition previously stressed by Berestycki-Nirenberg-Varadhan, Cabré was very able to improve the classical ABP estimate obtaining the maximum principle also in unbounded domains, such as infinite strips and open connected cones with closure different from the whole space. Now we introduce a new geometric condition that extends the result to a more general class of domains including the complements of hypersurfaces, as for instance the cut plane. The methods developed here allow us to deal with complete second-order equations, where the admissible first-order term, forced to be zero in a preceding result with Cafagna, depends on the geometry of the domain.  相似文献   
20.
In this paper we study some properties of sets, set-valued mappings, and extended-real-valued functions unified under the name of “sequential normal compactness.” These properties automatically hold in finite-dimensional spaces, while they play a major role in infinite-dimensional variational analysis. In particular, they are essential for calculus rules involving generalized differential constructions, for stability and metric regularity results and their broad applications, for necessary optimality conditions in constrained optimization and optimal control, etc. This paper contains principal results ensuring the preservation of sequential normal compactness properties under various operations over sets, set-valued mappings, and functions.  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