全文获取类型
收费全文 | 6657篇 |
免费 | 389篇 |
国内免费 | 847篇 |
专业分类
化学 | 100篇 |
晶体学 | 1篇 |
力学 | 159篇 |
综合类 | 109篇 |
数学 | 7251篇 |
物理学 | 273篇 |
出版年
2024年 | 10篇 |
2023年 | 108篇 |
2022年 | 63篇 |
2021年 | 84篇 |
2020年 | 115篇 |
2019年 | 169篇 |
2018年 | 183篇 |
2017年 | 179篇 |
2016年 | 183篇 |
2015年 | 140篇 |
2014年 | 269篇 |
2013年 | 513篇 |
2012年 | 213篇 |
2011年 | 331篇 |
2010年 | 320篇 |
2009年 | 461篇 |
2008年 | 497篇 |
2007年 | 502篇 |
2006年 | 454篇 |
2005年 | 406篇 |
2004年 | 328篇 |
2003年 | 325篇 |
2002年 | 312篇 |
2001年 | 234篇 |
2000年 | 251篇 |
1999年 | 240篇 |
1998年 | 201篇 |
1997年 | 201篇 |
1996年 | 127篇 |
1995年 | 72篇 |
1994年 | 70篇 |
1993年 | 29篇 |
1992年 | 30篇 |
1991年 | 25篇 |
1990年 | 18篇 |
1989年 | 7篇 |
1988年 | 18篇 |
1987年 | 6篇 |
1986年 | 11篇 |
1985年 | 20篇 |
1984年 | 24篇 |
1983年 | 15篇 |
1982年 | 18篇 |
1981年 | 13篇 |
1980年 | 23篇 |
1979年 | 20篇 |
1978年 | 19篇 |
1977年 | 14篇 |
1976年 | 7篇 |
1974年 | 4篇 |
排序方式: 共有7893条查询结果,搜索用时 0 毫秒
31.
Mauro Spera 《Journal of Functional Analysis》2003,197(1):110-139
In this paper, a rigorous construction of the S1-equivariant Dirac operator (i.e., Dirac-Ramond operator) on the space of (mean zero) loops in is given and its equivariant L2-index computed. Essential use is made of infinite tensor product representations of the canonical anticommutation relations algebra. 相似文献
32.
Satoshi Ishikawa 《Journal of Functional Analysis》2003,204(1):50-100
We investigate the totally geodesic Radon transform which assigns a function to its integration over totally geodesic symmetric submanifolds in Riemannian symmetric spaces of noncompact type. Our main concern is focused on the injectivity and support theorem. Our approach is based on the projection slice theorem relating the totally geodesic Radon transform and the Fourier transforms on symmetric spaces. Our approach also uses the study of geometry concerned with the totally geodesic symmetric subvarieties in Riemannian symmetric spaces in terms of the cell structure of the Satake compactifications. 相似文献
33.
Let X and Y be Banach spaces and ψ a continuous convex function on the unit interval [0,1] satisfying certain conditions. Let X⊕ψY be the direct sum of X and Y equipped with the associated norm with ψ. We show that X⊕ψY is uniformly convex if and only if X,Y are uniformly convex and ψ is strictly convex. As a corollary we obtain that the ?p,q-direct sum (not p=q=1 nor ∞), is uniformly convex if and only if X,Y are, where ?p,q is the Lorentz sequence space. These results extend the well-known fact for the ?p-sum . Some other examples are also presented. 相似文献
34.
Boris S. Mordukhovich Bingwu Wang 《Journal of Mathematical Analysis and Applications》2003,282(1):63-84
In this paper we study some properties of sets, set-valued mappings, and extended-real-valued functions unified under the name of “sequential normal compactness.” These properties automatically hold in finite-dimensional spaces, while they play a major role in infinite-dimensional variational analysis. In particular, they are essential for calculus rules involving generalized differential constructions, for stability and metric regularity results and their broad applications, for necessary optimality conditions in constrained optimization and optimal control, etc. This paper contains principal results ensuring the preservation of sequential normal compactness properties under various operations over sets, set-valued mappings, and functions. 相似文献
35.
A. Babakhani 《Journal of Mathematical Analysis and Applications》2003,278(2):434-442
Existence of positive solutions for the nonlinear fractional differential equation Dsu(x)=f(x,u(x)), 0<s<1, has been studied (S. Zhang, J. Math. Anal. Appl. 252 (2000) 804-812), where Ds denotes Riemann-Liouville fractional derivative. In the present work we study existence of positive solutions in case of the nonlinear fractional differential equation:
L(D)u=f(x,u),u(0)=0,0<x<1, 相似文献
36.
Luiza Amália Moraes Luis Romero Grados 《Journal of Mathematical Analysis and Applications》2003,281(2):575-586
Let Au(BG) be the Banach algebra of all complex valued functions defined on the closed unit ball BG of a complex Banach space G which are uniformly continuous on BG and holomorphic in the interior of BG, endowed with the sup norm. A characterization of the boundaries for Au(BG) is given in case G belongs to a class of Banach spaces that includes the pre-dual of a Lorentz sequence space studied by Gowers in Israel J. Math. 69 (1990) 129-151. The non-existence of the Shilov boundary for Au(BG) is also proved. 相似文献
37.
Chi-Kwong Li Ilya M. Spitkovsky 《Journal of Mathematical Analysis and Applications》2003,282(1):329-340
Existence of the fractional powers is established in Banach algebra setting, in terms of the numerical ranges of elements involved. The behavior of the spectra and (for Hermitian ∗-algebras satisfying some additional hypotheses) the ∗-numerical range under taking these powers also is investigated. 相似文献
38.
设(x,d,μ)是齐型空间.本文证明了分数次积分算子Iα与VMO函数构成的交换子I^ba是L^p(X)到L^q(X)的紧算子,其中α∈(0,1),1<p<q<∞且1/q=1/p—α。 相似文献
39.
关于L-fuzzy拓扑分离性的弱同胚不变性质 总被引:4,自引:0,他引:4
本文研究了一种新的弱同胚不变性质,它更具有一般性;证明了目前文献中所论述的各种分离性都是弱同胚不变性质,并且否定回答了王国俊提出的两个分离性问题。 相似文献
40.
建立了齐次群上伴随于Herz空间和Beurling代数的Hardy空间的分子分解理论.作为其应用.研究了中心强奇异Calderon-Zygmund算子在这些空间上的有界性. 相似文献