全文获取类型
收费全文 | 4884篇 |
免费 | 808篇 |
国内免费 | 989篇 |
专业分类
化学 | 74篇 |
晶体学 | 2篇 |
力学 | 145篇 |
综合类 | 337篇 |
数学 | 5355篇 |
物理学 | 768篇 |
出版年
2024年 | 28篇 |
2023年 | 104篇 |
2022年 | 119篇 |
2021年 | 127篇 |
2020年 | 112篇 |
2019年 | 87篇 |
2018年 | 67篇 |
2017年 | 124篇 |
2016年 | 128篇 |
2015年 | 135篇 |
2014年 | 290篇 |
2013年 | 213篇 |
2012年 | 234篇 |
2011年 | 294篇 |
2010年 | 321篇 |
2009年 | 284篇 |
2008年 | 333篇 |
2007年 | 341篇 |
2006年 | 328篇 |
2005年 | 329篇 |
2004年 | 284篇 |
2003年 | 313篇 |
2002年 | 203篇 |
2001年 | 245篇 |
2000年 | 202篇 |
1999年 | 222篇 |
1998年 | 172篇 |
1997年 | 166篇 |
1996年 | 162篇 |
1995年 | 145篇 |
1994年 | 108篇 |
1993年 | 106篇 |
1992年 | 99篇 |
1991年 | 89篇 |
1990年 | 91篇 |
1989年 | 56篇 |
1988年 | 6篇 |
1987年 | 8篇 |
1986年 | 3篇 |
1984年 | 1篇 |
1959年 | 2篇 |
排序方式: 共有6681条查询结果,搜索用时 31 毫秒
41.
岳华 《数学的实践与认识》2003,33(6):96-104
本文证明了可分无穷维 Hilbert空间上每个有界线性算子均可写成两个强不可约算子之和 .这回答了文献 [9]中提出一个公开问题 相似文献
42.
两相同部件温贮备可修的人机系统解的性质分析 总被引:4,自引:1,他引:4
郭卫华 《数学的实践与认识》2003,33(7):88-95
本文首先用强连续算子半群理论证明了两相同部件温贮备可修的人机系统动态非负解的存在唯一性 ,然后证明了 0是系统主算子的本征值 ,并得到 0本征值对应的本征向量是正的 ,从而系统存在稳态正解 . 相似文献
43.
44.
BinayakS.Choudhury 《分析论及其应用》2003,19(2):99-107
In the present paper we introduce a random iteration scheme for three random operators defined on a closed and convex subset of a uniformly convex Banach space and prove its convergence to a common fixed point of three random operators. The result is also an extersion of a known theorem in the corresponding non-random case. 相似文献
45.
YaolinJiang 《计算数学(英文版)》2003,21(3):367-374
In this paper we presented a convergence condition of paralle dynamic iteration meth-ods for a nonlinear system of differential-algebraic equations with a periodic constraint.The convergence criterion is decided by the spectral expressjon of a linear operator derived form system partitions.Numerical experiments given here confirm the theoretical work of the paper. 相似文献
46.
CongWenLIU JiHuaiSHI 《数学学报(英文版)》2003,19(1):187-200
In 1993,Ahern,Flores and Rudin showed that,if f is integrable over the unit ball BC^n of C^n and satisfies∫BC^nfoφdv=f(φ(0)) for every φ∈Aut(BC^n),then f is M-harmonic if and only if n≤11.The present paper is about an analogous question in the context of the unit ball Bn of R^n as well as in the weighted setting. 相似文献
47.
KunYuGUO 《数学学报(英文版)》2003,19(3):513-522
This paper is a brief and selective survey on classification of Hardy Submodules over the polydisk. The survey reports some progress in classification of Hardy submodules. 相似文献
48.
A family of subspaces of a complex separable Hilbert space is transitive if every bounded operator which leaves each of its
members invariant is scalar. This article surveys some results concerning transitive families of small cardinality, and adds
some new ones. The minimum cardinality of a transitive family in finite dimensions (greater than 2) is 4. In infinite dimensions
a transitive pair of linear manifolds exists but the minimum cardinality of a transitive family of dense operator ranges or
norm-closed subspaces is not known. However, a transitive family of dense operator ranges with 5 elements can be found, and
so can a transitive family of norm-closed subspaces with 4 elements. In finite dimensions (> 1) three nest algebras (corresponding
to maximal nests) can intersect in the scalar operators, but two cannot. It is not known if this is the case in infinite dimensions
for maximal nests of type ω + 1. Four such nest algebras can intersect in the scalar operators.
Received June 15, 2002, Accepted November 27, 2002 相似文献
49.
E.M.E.ZAYED 《数学学报(英文版)》2003,19(4):679-694
The asymptotic expansions of the trace of the heat kernel θ(t)=∑^∞v=1^exp(-tλv) for small positive t,where {λv} are the eigenvalues of the negative Laplacian -△n=-∑^ni=1(D/Dx^1)^2 in R^2(n=2 or 3),are studied for a general annular bounded domain Ω with a smooth inner boundary DΩ1 and a smooth outer boundary DΩ2,where a finite number of piecewise smooth Robin boundary conditions(D/Dnj γh)Ф=0 on the components Гj(j= 1,...,m) of (DΩ1 and on the components Гj (j=k 1,…,m) of of DΩ2 are considered such that DΩl=U^kj=lГj and DΩ2= U^m=k 1Гj and where the coefficients γj(j=1,...,m) are piecewise smooth positive functions. Some applications of θ(t) for an ideal gas enclosed in the general annular bounded domain Ω are given. Further results are also obtained. 相似文献
50.
等距算子的延拓、逼近及相关问题 总被引:11,自引:0,他引:11
本文介绍了等距算子从单位球面、从区域及从保距离1等条件下的各种等距廷拓问题;并介绍了(线性与非线性算子)等距算子的弱扰动、强扰动及渐近等距算子等问题.文中从历史到现状,概括了重要的研究结果,并指出了一些尚未解决的遗留问题. 相似文献