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   6514篇
  免费   210篇
  国内免费   709篇
化学   1114篇
晶体学   41篇
力学   62篇
综合类   102篇
数学   5297篇
物理学   817篇
  2024年   8篇
  2023年   53篇
  2022年   65篇
  2021年   85篇
  2020年   81篇
  2019年   148篇
  2018年   152篇
  2017年   174篇
  2016年   122篇
  2015年   105篇
  2014年   184篇
  2013年   974篇
  2012年   188篇
  2011年   307篇
  2010年   311篇
  2009年   359篇
  2008年   445篇
  2007年   441篇
  2006年   398篇
  2005年   365篇
  2004年   369篇
  2003年   329篇
  2002年   291篇
  2001年   188篇
  2000年   214篇
  1999年   172篇
  1998年   166篇
  1997年   173篇
  1996年   121篇
  1995年   78篇
  1994年   69篇
  1993年   54篇
  1992年   43篇
  1991年   28篇
  1990年   15篇
  1989年   23篇
  1988年   24篇
  1987年   15篇
  1986年   14篇
  1985年   10篇
  1984年   13篇
  1983年   3篇
  1982年   10篇
  1981年   6篇
  1980年   8篇
  1979年   10篇
  1978年   5篇
  1977年   4篇
  1976年   3篇
  1936年   5篇
排序方式: 共有7433条查询结果,搜索用时 38 毫秒
61.
In this paper we investigate Leibniz algebras whose quotient Lie algebra is a naturally graded filiform Lie algebra nn,1. We introduce a Fock module for the algebra nn,1 and provide classification of Leibniz algebras L whose corresponding Lie algebra L/I is the algebra nn,1 with condition that the ideal I is a Fock nn,1-module, where I is the ideal generated by squares of elements from L.We also consider Leibniz algebras with corresponding Lie algebra nn,1 and such that the action I×nn,1I gives rise to a minimal faithful representation of nn,1. The classification up to isomorphism of such Leibniz algebras is given for the case of n=4.  相似文献   
62.
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   
63.
We indicate similarities in the structure of two types of infinite-dimensional algebras, one introduced 28 years ago in connection with the mass problem of elementary particles and the other seven years ago in connection with spin systems (XY models). We show that these algebras can be considered as representations of a single Grand Algebra, the enveloping algebra of an affine Kac–Moody algebra built on the Poincaré Lie algebra. As an associative and coassociative bialgebra of operators, the latter representation of the grand algebra is a preferred nontrivial deformation of the Ising case bialgebra.  相似文献   
64.
An analog of the minimal unitary series representations for the deformed Virasoro algebra is constructed using vertex operators of the quantum affine algebra Uq(sl2). A similar construction is proposed for the elliptic algebra Aq,p(sl2).  相似文献   
65.
给出了双参数变形量子代数SU(2)q,s和SU(1,1)q,s的多模Jordan-Schwinger实现。  相似文献   
66.
ALGEBRAIC METHOD FOR VIBRATIONAL ENERGY SPECTRA OF H 2O AND NO 2   总被引:1,自引:0,他引:1  
文内提出一种研究H2O和NO2高激发伸缩振动的U(2)代数模型,在极限条件下,该模型退化为一种非谐和耦合的局域模模型,用该模型的六个可调参数拟合实验数据,算得的标准偏差比相应的非谐和耦合的局域模型算得的偏差要小  相似文献   
67.
Local U(1) symmetry in current algebra constructed by fermions has been found. The symmetry is related to the simplest q-deformation of N-fermions. We give the physical interpretation through the N-fermionic massless Thirring model. The Bethe ansatz wavefunction is also given.  相似文献   
68.
We calculate the continuous cohomology of the Lie algebra of meromorphic vector fields on a compact Riemann surface from the cohomology of the holomorphic vector fields on the open Riemann surface pointed in the poles. This cohomology has been given by Kawazumi. Our result shows the Feigin–Novikov conjecture.  相似文献   
69.
We observe that theN-state integrable chiral Potts model can be considered as a part of some new algebraic structure related to the six-vertex model. As a result, we obtain a functional equation which is supposed to determine all the eigenvalues of the chiral Potts model transfer matrix.  相似文献   
70.
Two new explicit Lie algebras are introduced for which the nonlinear integrable couplings of the Giachetti-Johnson (GJ) hierarchy and the Yang hierarchy are obtained, respectively. By employing the variational identity their Hamiltonian structures are also generated. The approach presented in the paper can also
provide nonlinear integrable couplings of other soliton hierarchies of evolution equations.  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