全文获取类型
收费全文 | 14350篇 |
免费 | 373篇 |
国内免费 | 1233篇 |
专业分类
化学 | 5632篇 |
晶体学 | 44篇 |
力学 | 72篇 |
综合类 | 37篇 |
数学 | 9335篇 |
物理学 | 836篇 |
出版年
2023年 | 29篇 |
2022年 | 68篇 |
2021年 | 82篇 |
2020年 | 97篇 |
2019年 | 320篇 |
2018年 | 301篇 |
2017年 | 208篇 |
2016年 | 183篇 |
2015年 | 210篇 |
2014年 | 366篇 |
2013年 | 1291篇 |
2012年 | 495篇 |
2011年 | 992篇 |
2010年 | 823篇 |
2009年 | 850篇 |
2008年 | 1104篇 |
2007年 | 1082篇 |
2006年 | 867篇 |
2005年 | 605篇 |
2004年 | 541篇 |
2003年 | 466篇 |
2002年 | 421篇 |
2001年 | 378篇 |
2000年 | 333篇 |
1999年 | 375篇 |
1998年 | 336篇 |
1997年 | 308篇 |
1996年 | 286篇 |
1995年 | 381篇 |
1994年 | 335篇 |
1993年 | 260篇 |
1992年 | 214篇 |
1991年 | 169篇 |
1990年 | 131篇 |
1989年 | 118篇 |
1988年 | 74篇 |
1987年 | 76篇 |
1986年 | 86篇 |
1985年 | 104篇 |
1984年 | 94篇 |
1983年 | 45篇 |
1982年 | 70篇 |
1981年 | 69篇 |
1980年 | 66篇 |
1979年 | 49篇 |
1978年 | 67篇 |
1977年 | 40篇 |
1976年 | 37篇 |
1975年 | 18篇 |
1974年 | 18篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
91.
The purpose of the present note is to establish some new delay integral inequalities, which provide explicit bounds on unknown functions and generalize some results of Li et al. [Some new delay integral inequalities and their applications, J. Comput. Appl. Math. 180 (2005) 191–200]. The inequalities given here can be used to investigate the qualitative properties of certain delay differential equations and delay integral equations. 相似文献
92.
Brian Hartwig 《Linear algebra and its applications》2007,422(1):219-235
Recently Terwilliger and the present author found a presentation for the three-point sl2 loop algebra via generators and relations. To obtain this presentation we defined a Lie algebra ? by generators and relations and displayed an isomorphism from ? to the three-point sl2 loop algebra. In this paper we classify the finite-dimensional irreducible ?-modules. 相似文献
93.
Katharina Habermann Lutz Habermann Paul Rosenthal 《Calculus of Variations and Partial Differential Equations》2007,30(2):137-152
A Yang–Mills theory in a purely symplectic framework is developed. The corresponding Euler–Lagrange equations are derived
and first integrals are given. We relate the results to the work of Bourgeois and Cahen on preferred symplectic connections. 相似文献
94.
J. Haglund 《Advances in Mathematics》2003,175(2):319-334
We introduce the distribution function Fn(q,t) of a pair of statistics on Catalan words and conjecture Fn(q,t) equals Garsia and Haiman's q,t-Catalan sequence Cn(q,t), which they defined as a sum of rational functions. We show that Fn,s(q,t), defined as the sum of these statistics restricted to Catalan words ending in s ones, satisfies a recurrence relation. As a corollary we are able to verify that Fn(q,t)=Cn(q,t) when t=1/q. We also show the partial symmetry relation Fn(q,1)=Fn(1,q). By modifying a proof of Haiman of a q-Lagrange inversion formula based on results of Garsia and Gessel, we obtain a q-analogue of the general Lagrange inversion formula which involves Catalan words grouped according to the number of ones at the end of the word. 相似文献
95.
Rosário Fernandes 《Linear algebra and its applications》2007,422(1):1-16
We consider the general problem of determining the maximum possible multiplicity of an eigenvalue in a Hermitian matrix whose graph contains exactly one cycle. For some cases we express that maximum multiplicity in terms of certain parameters associated with the graph. 相似文献
96.
Brian A. Hagler 《Linear algebra and its applications》2007,422(1):100-118
Definitions, theorems and examples are established for a general model of Laurent polynomial spaces and ordered orthogonal Laurent polynomial sequences, ordered with respect to ordered bases and orthogonal with respect to inner products ·=L°⊙ decomposed into transition functional ⊙ and strong moment functional, or, more generally, sample functional L couplings. Under this formulation that is shown to subsume those in the existing literature, new fundamental results are produced, including necessary and sufficient conditions for ordered OLPS to be sequences of nth numerators of continued fractions, in contrast to the classical result concerning nth denominators which is shown to hold only in special cases. 相似文献
97.
Conrad Plaut 《Topology and its Applications》2006,153(14):2430-2444
This paper develops the basic theory of quotients of uniform spaces via sufficiently nice group actions. We generalize and unify two fundamental constructions: quotients of topological groups via closed normal subgroups and quotients of metric spaces via actions by isometries. Basic results about inverse limits of topological groups are extended to inverse limits of group actions on uniform spaces, and notions of prodiscrete action and generalized covering map are introduced. 相似文献
98.
S?awomir Solecki 《Topology and its Applications》2007,154(12):2462-2464
Let I0 be the σ-ideal of subsets of a Polish group generated by Borel sets which have perfectly many pairwise disjoint translates. We prove that a Fubini-type theorem holds between I0 and the σ-ideals of Haar measure zero sets and of meager sets. We use this result to give a simple proof of a generalization of a theorem of Balcerzak-Ros?anowski-Shelah stating that I0 on N2 strongly violates the countable chain condition. 相似文献
99.
In this paper we present several results about local MV-algebras, extending existing results given for MV-chains. The role
of local MV-algebras in sheaf representation and weak boolean product is stressed and the relationship of local MV-algebras
with varieties of MV-algebras is analyzed.
Presented by S. Pulmannova.
Received November 11, 2005; accepted in final form December 20, 2005. 相似文献
100.