全文获取类型
收费全文 | 5102篇 |
免费 | 257篇 |
国内免费 | 517篇 |
专业分类
化学 | 1600篇 |
晶体学 | 15篇 |
力学 | 115篇 |
综合类 | 42篇 |
数学 | 3515篇 |
物理学 | 589篇 |
出版年
2024年 | 5篇 |
2023年 | 59篇 |
2022年 | 90篇 |
2021年 | 102篇 |
2020年 | 136篇 |
2019年 | 141篇 |
2018年 | 140篇 |
2017年 | 126篇 |
2016年 | 82篇 |
2015年 | 107篇 |
2014年 | 163篇 |
2013年 | 694篇 |
2012年 | 142篇 |
2011年 | 188篇 |
2010年 | 153篇 |
2009年 | 248篇 |
2008年 | 297篇 |
2007年 | 322篇 |
2006年 | 291篇 |
2005年 | 308篇 |
2004年 | 260篇 |
2003年 | 254篇 |
2002年 | 238篇 |
2001年 | 183篇 |
2000年 | 181篇 |
1999年 | 153篇 |
1998年 | 160篇 |
1997年 | 155篇 |
1996年 | 95篇 |
1995年 | 63篇 |
1994年 | 45篇 |
1993年 | 50篇 |
1992年 | 43篇 |
1991年 | 22篇 |
1990年 | 13篇 |
1989年 | 23篇 |
1988年 | 20篇 |
1987年 | 10篇 |
1986年 | 11篇 |
1985年 | 22篇 |
1984年 | 16篇 |
1983年 | 7篇 |
1982年 | 11篇 |
1981年 | 10篇 |
1980年 | 8篇 |
1979年 | 6篇 |
1978年 | 7篇 |
1977年 | 4篇 |
1976年 | 4篇 |
1974年 | 3篇 |
排序方式: 共有5876条查询结果,搜索用时 31 毫秒
1.
《Indagationes Mathematicae》2021,32(6):1229-1239
2.
3.
《Indagationes Mathematicae》2022,33(1):218-237
We define the notion of basic set data for finite groups (building on the notion of basic set, but including an order on the irreducible characters as part of the structure), and we prove that the Springer correspondence provides basic set data for Weyl groups. Then we use this to determine explicitly the modular Springer correspondence for classical types (defined over a base field of odd characteristic , and with coefficients in a field of odd characteristic ): the modular case is obtained as a restriction of the ordinary case to a basic set. In order to do so, we compare the order on bipartitions introduced by Dipper and James with the order induced by the Springer correspondence. We provide a quick proof, by sorting characters according to the dimension of the corresponding Springer fibre, an invariant which is directly computable from symbols. 相似文献
4.
An oriented tetrahedron defined on four vertices is a set of four cyclic triples with the property that any ordered pair of vertices is contained in exactly one of the cyclic triples. A tetrahedral quadruple system of order with index , denoted by , is a pair , where is an ‐set and is a set of oriented tetrahedra (blocks) such that every cyclic triple on is contained in exactly members of . A is pure if there do not exist two blocks with the same vertex set. When , the spectrum of a pure TQS has been completely determined by Ji. In this paper, we show that there exists a pure if and only if and . A corollary is that a simple also exists if and only if and . 相似文献
5.
张志让 《数学年刊A辑(中文版)》2006,(2)
如果群 G 的所有真商群都是 FO-群,但是群 G 本身不是 FO-群,则称 G 为外 FO-群,本文将给出外 FO-群完全的结构描述. 相似文献
6.
A FUNDAMENTAL SOLUTION FOR THE LAPLACE OPERATOR ON THE QUATERNIONIC HEISENBERG GROUP 总被引:2,自引:0,他引:2
朱理 《数学物理学报(B辑英文版)》2002,22(3)
In this paper, the author studies the Laplace operator on the quaternionic Heisenberg group, construct a fundamental solution for it and use this solution to prove the Lp-boundedness and the weak (1-1) boundedness of certain singular convolution operators on the quaternionic Heisenberg group. 相似文献
7.
A (w,r) cover‐free family is a family of subsets of a finite set such that no intersection of w members of the family is covered by a union of r others. A (w,r) superimposed code is the incidence matrix of such a family. Such a family also arises in cryptography as the concept of key distribution pattern. In the present paper, we give some new results on superimposed codes. First we construct superimposed codes from super‐simple designs which give us results better than superimposed codes constructed by other known methods. Next we prove the uniqueness of the (1,2) superimposed code of size 9 × 12, the (2,2) superimposed code of size 14 × 8, and the (2,3) superimposed code of size 30 × 10. Finally, we improve numerical values of upper bounds for the asymptotic rate of some (w,r) superimposed codes. © 2004 Wiley Periodicals, Inc. 相似文献
8.
Mrio J. Edmundo 《Mathematical Logic Quarterly》2005,51(6):639-641
We show that if G is a definably compact, definably connected definable group defined in an arbitrary o‐minimal structure, then G is divisible. Furthermore, if G is defined in an o‐minimal expansion of a field, k ∈ ? and pk : G → G is the definable map given by pk (x ) = xk for all x ∈ G , then we have |(pk )–1(x )| ≥ kr for all x ∈ G , where r > 0 is the maximal dimension of abelian definable subgroups of G . (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
9.
In this paper we continue to study the spectral norms and their completions ([4]) in the case of the algebraic closure $ \overline {\mathbb Q} $ of ? in ?. Let $ \widetilde{\overline{\mathbb{Q}}} $ be the completion of $ \overline {\mathbb Q} $ relative to the spectral norm. We prove that $ \widetilde{\overline{\mathbb{Q}}} $ can be identified with the R‐subalgebra of all symmetric functions of C(G), where C(G) denotes the ?‐Banach algebra of all continuous functions defined on the absolute Galois group G = Gal$ {\overline {\mathbb Q}} / {\mathbb Q} $. We prove that any compact, closed to conjugation subset of ? is the pseudo‐orbit of a suitable element of $ \widetilde{\overline{\mathbb{Q}}} $. We also prove that the topological closure of any algebraic number field in $ \widetilde{\overline{\mathbb{Q}}} $ is of the form $\widetilde{\mathbb{Q}[x]}$ with x in $ \widetilde{\overline{\mathbb{Q}}} $. 相似文献
10.
In the present paper we give necessary and sufficient conditions for the subgroup separability of the fundamental group of a finite graph of groups with finitely generated abelian vertex groups.