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   6743篇
  免费   295篇
  国内免费   862篇
化学   54篇
力学   85篇
综合类   120篇
数学   6887篇
物理学   754篇
  2024年   9篇
  2023年   64篇
  2022年   70篇
  2021年   101篇
  2020年   85篇
  2019年   161篇
  2018年   179篇
  2017年   183篇
  2016年   139篇
  2015年   117篇
  2014年   204篇
  2013年   1025篇
  2012年   201篇
  2011年   309篇
  2010年   296篇
  2009年   400篇
  2008年   506篇
  2007年   479篇
  2006年   413篇
  2005年   348篇
  2004年   344篇
  2003年   331篇
  2002年   333篇
  2001年   225篇
  2000年   246篇
  1999年   213篇
  1998年   203篇
  1997年   210篇
  1996年   118篇
  1995年   72篇
  1994年   49篇
  1993年   36篇
  1992年   26篇
  1991年   21篇
  1990年   13篇
  1989年   14篇
  1988年   16篇
  1987年   5篇
  1986年   11篇
  1985年   10篇
  1984年   21篇
  1983年   12篇
  1982年   10篇
  1981年   9篇
  1980年   10篇
  1979年   11篇
  1978年   14篇
  1977年   9篇
  1976年   6篇
  1936年   5篇
排序方式: 共有7900条查询结果,搜索用时 46 毫秒
1.
2.
3.
4.
5.
In this paper, the deformation of the Heisenberg algebra, consistent with both the generalized uncertainty principle and doubly special relativity, has been analyzed. It has been observed that, though this algebra can give rise to fractional derivative terms in the corresponding quantum mechanical Hamiltonian, a formal meaning can be given to them by using the theory of harmonic extensions of function. Depending on this argument, the expression of the propagator of the path integral corresponding to the deformed Heisenberg algebra, has been obtained. In particular, the consistent expression of the one dimensional free particle propagator has been evaluated explicitly. With this propagator in hand, it has been shown that, even in free particle case, normal generalized uncertainty principle and doubly special relativity show very much different result.  相似文献   
6.
In this note, we use inexact Newton-like methods to find solutions of nonlinear operator equations on Banach spaces with a convergence structure. Our technique involves the introduction of a generalized norm as an operator from a linear space into a partially ordered Banach space. In this way, the metric properties of the examined problem can be analyzed more precisely. Moreover, this approach allows us to derive from the same theorem, on the one hand, semilocal results of Kantorovich-type, and on the other hand, global results based on monotonicity considerations. By imposing very general Lipschitz-like conditions on the operators involved, on the one hand, we cover a wider range of problems, and on the other hand, by choosing our operators appropriately, we can find sharper error bounds on the distances involved than before. Furthermore, we show that special cases of our results reduce to the corresponding ones already in the literature. Finally, several examples are being provided where our results compare favorably with earlier ones.  相似文献   
7.
This paper through discussing subdifferentiability and convexity of convex functions shows that a Banach space admits an equivalent uniformly [locally uniformly, strictly] convex norm if and only if there exists a continuous uniformly [locally uniformly, strictly] convex function on some nonempty open convex subset of the space and presents some characterizations of super-reflexive Banach spaces. Supported by NSFC  相似文献   
8.
Numerical integration of ordinary differential equations on manifolds   总被引:4,自引:0,他引:4  
Summary This paper is concerned with the problem of developing numerical integration algorithms for differential equations that, when viewed as equations in some Euclidean space, naturally evolve on some embedded submanifold. It is desired to construct algorithms whose iterates also evolve on the same manifold. These algorithms can therefore be viewed as integrating ordinary differential equations on manifolds. The basic method “decouples” the computation of flows on the submanifold from the numerical integration process. It is shown that two classes of single-step and multistep algorithms can be posed and analyzed theoretically, using the concept of “freezing” the coefficients of differential operators obtained from the defining vector field. Explicit third-order algorithms are derived, with additional equations augmenting those of their classical counterparts, obtained from “obstructions” defined by nonvanishing Lie brackets.  相似文献   
9.
Algebra matrix and similarity classification of operators   总被引:1,自引:0,他引:1  
In this paper, by the Gelfand representation theory and the Silov idempotents theorem, we first obtain a central decomposition theorem related to a unital semi-simple n-homogeneous Banach algebra, and then give a similarity classification of two strongly irreducible Cowen-Douglas operators using this theorem.  相似文献   
10.
We give a coring version for the duality theorem for actions and coactions of a finitely generated projective Hopf algebra. We also provide a coring analogue for a theorem of H.-J. Schneider, which generalizes and unifies the duality theorem for finite Hopf algebras and its refinements. This paper was written while the first author visited the Mathematics Departments of Syracuse University and California State University Dominguez Hills. He would like to thank both departments for their hospitality.  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