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   2233篇
  免费   130篇
  国内免费   309篇
化学   112篇
晶体学   1篇
力学   120篇
综合类   48篇
数学   2271篇
物理学   120篇
  2024年   4篇
  2023年   23篇
  2022年   29篇
  2021年   32篇
  2020年   38篇
  2019年   53篇
  2018年   63篇
  2017年   67篇
  2016年   64篇
  2015年   56篇
  2014年   79篇
  2013年   248篇
  2012年   106篇
  2011年   95篇
  2010年   93篇
  2009年   136篇
  2008年   175篇
  2007年   169篇
  2006年   137篇
  2005年   124篇
  2004年   106篇
  2003年   110篇
  2002年   122篇
  2001年   72篇
  2000年   67篇
  1999年   80篇
  1998年   65篇
  1997年   48篇
  1996年   40篇
  1995年   33篇
  1994年   25篇
  1993年   15篇
  1992年   13篇
  1991年   15篇
  1990年   9篇
  1989年   8篇
  1988年   4篇
  1987年   3篇
  1986年   3篇
  1985年   9篇
  1984年   7篇
  1983年   2篇
  1982年   8篇
  1981年   4篇
  1980年   7篇
  1979年   1篇
  1978年   2篇
  1977年   2篇
  1976年   1篇
排序方式: 共有2672条查询结果,搜索用时 15 毫秒
51.
Let A be a basic hereditary artin algebra and R = A Q be the trivial extension of A by its minimal injective cogenerator Q. We construct some right (left) almost split morphisms and irreducible morphisms in modR through the corresponding morphisms in modA. Furthermore, we can determine its almost split sequences in modR.  相似文献   
52.
The phenomenon of extraordinary acoustic transmission ( eat) in a resonator, which has recently been investigated experimentally, is studied theoretically. It is shown that the combination of a single propagating mode and a symmetry orthogonal to the direction of propagation for a resonator leads to eat. This is accomplished by decomposing the problem using symmetry, the Blaschke product and the properties of functions of a single complex variable which have modulus one on the real axis. The conditions of a resonator requires that the solution has singularities in the analytic extension to complex frequencies (resonances) and it is precisely near these resonances that we observe eat. The condition of a Blaschke product requires that there is a zero at the complex conjugate of the singularity and eat occurs when the solution on the real axis passes between these complex conjugate pairs of poles and zeros. A detailed numerical study of the problem is conducted and we show that once the single mode of propagation or the symmetry is broken then eat (at least perfect transmission) no longer holds generally.  相似文献   
53.
《Optimization》2012,61(5):689-707
We study local Lipschitz continuity and interpolation properties of some classes of increasing functions defined on the cone Rn ++ of n-vectors with positive coordinates. We also study the so-called self-conjugate increasing positively homogeneous functions.  相似文献   
54.
《Optimization》2012,61(9):1075-1086
In this article, we establish some relationships between a solution of generalized vector variational-like inequalities and an efficient solution or a weakly efficient solution to the nonsmooth vector optimization problem under the assumptions of pseudoinvexity or invariant pseudomonotonicity. Our results extend and improve the corresponding results in the literature.  相似文献   
55.
56.
For curvilinear Lipschitz polyhedral domains Ω, explicit characterizations of the tangential trace spaces of H 1(Ω) are presented. These extend the original characterizations given by Buffa and Ciarlet that hold on Lipschitz polyhedral domains with plane faces. The tangential trace spaces of H 1(Ω) are fundamental for the definition, analysis and intuitive understanding of the trace spaces of H ( curl ,Ω) and therefore, more general characterizations of the latter are obtained at the same time. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   
57.
Let be the class of all sense‐preserving homeomorphic self‐mappings of . The aim of this paper is twofold. First, we obtain Heinz‐type inequality for (K,K)‐quasiconformal mappings satisfying inhomogeneous biharmonic equation Δ(Δω) = g in unit disk with associated boundary value conditions and . Second, we establish biLipschitz continuity for (K,K)‐quasiconformal mappings satisfying aforementioned inhomogeneous biharmonic equation when and are small enough.  相似文献   
58.
Recently Lipschitz equivalence of self‐similar sets on has been studied extensively in the literature. However for self‐affine sets the problem is more awkward and there are very few results. In this paper, we introduce a w‐Lipschitz equivalence by repacing the Euclidean norm with a pseudo‐norm w. Under the open set condition, we prove that any two totally disconnected integral self‐affine sets with a common matrix are w‐Lipschitz equivalent if and only if their digit sets have equal cardinality. The main methods used are the technique of pseudo‐norm and Gromov hyperbolic graph theory on iterated function systems.  相似文献   
59.
The aim of this paper is to establish a well‐posedness result for a boundary value problem of transmission‐type for the standard and generalized Brinkman systems in two Lipschitz domains in , the former being bounded, and the latter, its complement in . As a first step, we establish a well‐posedness result for a transmission problem for the standard Brinkman systems on complementary Lipschitz domains in by making use of the Potential theory developed for such a system. As a second step, we prove our desired result (in L2‐based Sobolev spaces) by using a method based on Fredholm operator theory and the well‐posedness result from the previous step.  相似文献   
60.
A graph G with at least 2m+2 vertices is said to be distance d m-extendable if, for any matching M of G with m edges in which the edges lie at distance at least d pairwise, there exists a perfect matching of G containing M. In this paper we prove that every 5-connected triangulation on the projective plane of even order is distance 3 7-extendable and distance 4 m-extendable for any m.  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