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   1011篇
  国内免费   167篇
  完全免费   55篇
  数学   1233篇
  2020年   23篇
  2019年   26篇
  2018年   21篇
  2017年   20篇
  2016年   9篇
  2015年   12篇
  2014年   25篇
  2013年   174篇
  2012年   16篇
  2011年   40篇
  2010年   25篇
  2009年   47篇
  2008年   79篇
  2007年   82篇
  2006年   68篇
  2005年   53篇
  2004年   60篇
  2003年   57篇
  2002年   55篇
  2001年   51篇
  2000年   49篇
  1999年   45篇
  1998年   49篇
  1997年   52篇
  1996年   23篇
  1995年   13篇
  1994年   13篇
  1993年   11篇
  1992年   7篇
  1991年   7篇
  1990年   4篇
  1989年   7篇
  1988年   1篇
  1987年   3篇
  1986年   3篇
  1985年   1篇
  1984年   1篇
  1980年   1篇
排序方式: 共有1233条查询结果,搜索用时 46 毫秒
1.
Structure of Degenerate Block Algebras   总被引:12,自引:0,他引:12  
Given a non-trivial torsion-free abelian group (A,+,Q), a field F of characteristic 0, and a non-degenerate bi-additive skew-symmetric map : A A F, we define a Lie algebra = (A, ) over F with basis {ex | x A/{0}} and Lie product [ex,ey] = (x,y)ex+y. We show that is endowed uniquely with a non-degenerate symmetric invariant bilinear form and the derivation algebra Der of is a complete Lie algebra. We describe the double extension D( , T) of by T, where T is spanned by the locally finite derivations of , and determine the second cohomology group H2(D( , T),F) using anti-derivations related to the form on D( , T). Finally, we compute the second Leibniz cohomology groups HL2( , F) and HL2(D( , T), F).2000 Mathematics Subject Classification: 17B05, 17B30This work was supported by the NNSF of China (19971044), the Doctoral Programme Foundation of Institution of Higher Education (97005511), and the Foundation of Jiangsu Educational Committee.  相似文献
2.
Hochschild cohomology of truncated basic cycle   总被引:9,自引:0,他引:9  
Dimensions of the Hochschild cohomology groups of a truncated algebra of a basic cycle are explicitly given. Project supported by the State Education Commission of China, the Chinese Academy of Sciences and the National Natural Science Foundation of China.  相似文献
3.
Abel范畴中态射乘积诱导的短正合列及其应用   总被引:8,自引:0,他引:8       下载免费PDF全文
李桃生 《数学学报》1995,38(6):732-737
本文给出了Abel范畴中态射乘积αβγ诱导的短正合列的立体交换图。其中共有7个3×3平面,30条线。每一条线(两端的零对象省略)都是一个短正合列.这些短正合列用到p-除环上的矩阵,可以导出一系列矩阵秩的恒等式,它不仅推广了域上矩阵秩的结果,还能得到一些新的关系式.  相似文献
4.
油藏渗流问题的新模型及其精确解   总被引:5,自引:1,他引:4  
5.
模李超代数研究的若干进展   总被引:5,自引:0,他引:5  
张永正  王颖  张庆成 《数学进展》2002,31(6):495-502
近几年,模李超代数(即素特征域上的李超代数)的研究取得了一些进展。本文分析以下6个方面介绍近几年在模李超代数研究中取得的一些新结果。1,限制李超代数,2,Cartan型模李超代数;3,深度1的Z-阶化李超代数;4,深度1的滤过李超代数。5;Cartan型模李超代数的某些内蕴性质;6,公开的问题。  相似文献
6.
Deformation Theory and The Computation of Zeta Functions   总被引:3,自引:0,他引:3  
We present a new approach to the problem of computing the zetafunction of a hypersurface over a finite field. For a hypersurfacedefined by a polynomial of degree d in n variables over thefield of q elements, one desires an algorithm whose runningtime is a polynomial function of dn log(q). (Here we assumed 2, for otherwise the problem is easy.) The case n = 1 isrelated to univariate polynomial factorisation and is comparativelystraightforward. When n = 2 one is counting points on curves,and the method of Schoof and Pila yields a complexity of , where the function Cd depends exponentiallyon d. For arbitrary n, the theorem of the author and Wan givesa complexity which is a polynomial function of (pdn log(q))n,where p is the characteristic of the field. A complexity estimateof this form can also be achieved for smooth hypersurfaces usingthe method of Kedlaya, although this has only been worked outin full for curves. The new approach we present should yielda complexity which is a small polynomial function of pdn log(q).In this paper, we work this out in full for Artin–Schreierhypersurfaces defined by equations of the form ZpZ= f, where the polynomial f has a diagonal leading form. Themethod utilises a relative p-adic cohomology theory for familiesof hypersurfaces, due in essence to Dwork. As a corollary ofour main theorem, we obtain the following curious result. Letf be a multivariate polynomial with integer coefficients whoseleading form is diagonal. There exists an explicit deterministicalgorithm which takes as input a prime p, outputs the numberof solutions to the congruence equation f = 0 op, and runs in bit operations, for any >0. This improves upon the elementary estimate of bit operations, where n is the number of variables,which can be achieved using Berlekamp's root counting algorithm.2000 Mathematics Subject Classification 11Y99, 11M38, 11T99.  相似文献
7.
Line bundles on non-primary Hopf manifolds   总被引:3,自引:0,他引:3  
Let X be a Hopf manifolds with Abelian fundamental group, L any flat line bundle on X, we give a formula for computing explicitly the cohomology Hq(X,Ωp(L) using the method of group action and the generalized Douady sequence.  相似文献
8.
The f-depth of an ideal on a module   总被引:2,自引:0,他引:2  
Let be an ideal of a Noetherian local ring and a finitely generated -module. The f-depth of on is the least integer such that the local cohomology module is not Artinian. This paper presents some part of the theory of f-depth including characterizations of f-depth and a relation between f-depth and f-modules.

  相似文献

9.
Suppose a group G acts on a Gromov-hyperbolic space X properlydiscontinuously. If the limit set L(G) of the action has atleast three points, then the second bounded cohomology groupof is infinite dimensional. For example, if M is a complete, pinched negatively curved Riemannianmanifold with finite volume, then is infinite dimensional. As an application, we show that ifG is a knot group with GZ, then is infinite dimensional. 1991 Mathematics Subject Classification:primary 20F32; secondary 53C20, 57M25.  相似文献
10.
ON THE COHOMOLOGY OF GENERALIZED RESTRICTED LIE ALGEBRAS   总被引:2,自引:0,他引:2  
0.IntroductionThispaperisaimedatdevelopingthecohomologytheoryofmodularLiealgebrasandthendeterminingthefirstcohomologygroupsofCartantypeLiealgebras.AsgeneralizationoftheconceptofrestrictedLiealgebras,ageneralizedrestrictedLiealgebra(GRLiealgebra)wasintroducedin[21],whichisassociatedwithabasisandamappingofthebasisintotheLiealgebrasatisfyingthegeneralized-restrictednessconditions.Generalizedrestrictedrepresentations(GRrepresentations)werethenintroduced,whichcanbereducedtotherepresentationsofa…  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