全文获取类型
收费全文 | 3474篇 |
免费 | 63篇 |
国内免费 | 9篇 |
专业分类
化学 | 83篇 |
晶体学 | 4篇 |
力学 | 16篇 |
综合类 | 2篇 |
数学 | 3262篇 |
物理学 | 179篇 |
出版年
2023年 | 5篇 |
2022年 | 9篇 |
2021年 | 5篇 |
2020年 | 2篇 |
2019年 | 87篇 |
2018年 | 78篇 |
2017年 | 40篇 |
2016年 | 31篇 |
2015年 | 44篇 |
2014年 | 97篇 |
2013年 | 213篇 |
2012年 | 97篇 |
2011年 | 200篇 |
2010年 | 210篇 |
2009年 | 268篇 |
2008年 | 269篇 |
2007年 | 315篇 |
2006年 | 242篇 |
2005年 | 141篇 |
2004年 | 123篇 |
2003年 | 129篇 |
2002年 | 86篇 |
2001年 | 59篇 |
2000年 | 78篇 |
1999年 | 91篇 |
1998年 | 73篇 |
1997年 | 59篇 |
1996年 | 78篇 |
1995年 | 76篇 |
1994年 | 69篇 |
1993年 | 52篇 |
1992年 | 32篇 |
1991年 | 11篇 |
1990年 | 15篇 |
1989年 | 17篇 |
1988年 | 9篇 |
1987年 | 10篇 |
1986年 | 8篇 |
1985年 | 18篇 |
1984年 | 30篇 |
1983年 | 7篇 |
1982年 | 22篇 |
1981年 | 15篇 |
1980年 | 6篇 |
1978年 | 7篇 |
1977年 | 5篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有3546条查询结果,搜索用时 15 毫秒
991.
We survey results and techniques in the topological study of simplicial complexes
of (di-, multi-, hyper-)graphs whose node degrees are bounded from above. These
complexes have arisen in a variety of contexts in the literature. The most well-known examples
are the matching complex and the chessboard complex. The topics covered here
include computation of Betti numbers, representations of the symmetric group on rational
homology, torsion in integral homology, homotopy properties, and connections with other
fields.In memory of Gian-Carlo Rota 相似文献
992.
993.
Jinghua Wang 《Journal of Differential Equations》2003,189(1):1-16
In this paper, we study a generalized Burgers equation ut+(u2)x=tuxx, which is a non-uniformly parabolic equation for t>0. We show the existence and uniqueness of classical solutions to the initial-value problem of the generalized Burgers equation with rough initial data belonging to . 相似文献
994.
The Cauchy transform of a measure has been used to study the analytic capacity and uniform rectifiability of subsets in . Recently, Lund et al. (Experiment. Math. 7 (1998) 177) have initiated the study of such transform F of self-similar measure. In this and the forecoming papers (Starlikeness and the Cauchy transform of some self-similar measures, in preparation; The Cauchy transform on the Sierpinski gasket, in preparation), we study the analytic and geometric behavior as well as the fractal behavior of the transform F. The main concentration here is on the Laurent coefficients {an}n=0∞ of F. We give asymptotic formulas for {an}n=0∞ and for F(k)(z) near the support of μ, hence the precise growth rates on |an| and |F(k)| are determined. These formulas are connected with some multiplicative periodic functions, which reflect the self-similarity of μ and K. As a by-product, we also discover new identities of certain infinite products and series. 相似文献
995.
S. Oltra S. Romaguera E. A. Sánchez-Pérez 《Rendiconti del Circolo Matematico di Palermo》2002,51(1):151-162
We show that the bicompletion of a weightable quasi-metric space is a weightable quasi-metric space. From this result we deduce
that any partial metric space has an (up to isometry) unique partial metric bicompletion. Some other consequences are derived.
In particular, applications to two interesting examples of partial metric spaces which appear in Computer Science, as the
domain of words and the complexity space, are given.
The second and third listed authors are partially supported by grants from Spanish Ministry of Science and Technology, BFM
2000-III, and Polytechnical University of Valencia. 相似文献
996.
Weyl's theorem for operator matrices 总被引:11,自引:0,他引:11
Woo Young Lee 《Integral Equations and Operator Theory》1998,32(3):319-331
Weyl's theorem holds for an operator when the complement in the spectrum of the Weyl spectrum coincides with the isolated points of the spectrum which are eigenvalues of finite multiplicity. By comparison Browder's theorem holds for an operator when the complement in the spectrum of the Weyl spectrum coincides with Riesz points. Weyl's theorem and Browder's theorem are liable to fail for 2×2 operator matrices. In this paper we explore how Weyl's theorem and Browder's theorem survive for 2×2 operator matrices on the Hilbert space.Supported in part by BSRI-97-1420 and KOSEF 94-0701-02-01-3. 相似文献
997.
Alexander Gorokhovsky 《K-Theory》1998,15(3):253-268
In this article we construct explicit cocycles in the AlexanderSpanier cohomological complex, representing the Chern character of an element in Ktheory 相似文献
998.
THEBLOW┐UPPROPERTYFORASYSTEMOFHEATEQUATIONSWITHNONLINEARBOUNDARYCONDITIONSLINZHIGUI,XIECHUNHONGANDWANGMINGXINAbstract.Thispap... 相似文献
999.
We propose an elementary definition of the dynamical entropy for a discrete-time quantum dynamical system. We apply our construction to classical dynamical systems and to the shift on a quantum spin chain. In the first case, we recover the Kolmogorov-Sinai invariant and, for the second, we find the mean entropy of the invariant state plus the logarithm of the dimension of the single-spin space. 相似文献
1000.
We denote byK
k
,k, 2, the set of allk-uniform hypergraphsK which have the property that every element subset of the base ofK is a subset of one of the hyperedges ofK. So, the only element inK
2
2
are the complete graphs. If is a subset ofK
k
then there is exactly one homogeneous hypergraphH
whose age is the set of all finite hypergraphs which do not embed any element of . We callH
-free homogeneous graphsH
n
have been shown to be indivisible, that is, for any partition ofH
n
into two classes, oue of the classes embeds an isomorphic copy ofH
n
. [5]. Here we will investigate this question of indivisibility in the more general context of-free homogeneous hypergraphs. We will derive a general necessary condition for a homogeneous structure to be indivisible and prove that all-free hypergraphs for K
k
with 3 are indivisible. The-free hypergraphs with K
k
2
satisfy a weaker form of indivisibility which was first shown by Henson [2] to hold forH
n
. The general necessary condition for homogeneous structures to be indivisible will then be used to show that not all-free homogeneous hypergraphs are indivisible.This research has been supported by NSERC grant 69–1325. 相似文献