全文获取类型
收费全文 | 6637篇 |
免费 | 397篇 |
国内免费 | 846篇 |
专业分类
化学 | 99篇 |
晶体学 | 1篇 |
力学 | 156篇 |
综合类 | 109篇 |
数学 | 7247篇 |
物理学 | 268篇 |
出版年
2024年 | 9篇 |
2023年 | 107篇 |
2022年 | 62篇 |
2021年 | 83篇 |
2020年 | 113篇 |
2019年 | 167篇 |
2018年 | 182篇 |
2017年 | 179篇 |
2016年 | 183篇 |
2015年 | 140篇 |
2014年 | 268篇 |
2013年 | 512篇 |
2012年 | 212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 | 250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7880条查询结果,搜索用时 15 毫秒
51.
Frank Morgan 《Annals of Global Analysis and Geometry》2006,30(1):73-79
In a product M
1 × M
2 of Riemannian manifolds, the least perimeter required to enclose given volume among general regions is at least 1/√ 2 times that among regions of product form, assuming that the isoperimetric profiles of M
1 and M
2 are concave. This result sharpens earlier work of Grigor'yan, generalizes results of Bollobás and Leader and of Barthe, and yields a lower bound on the Cheeger isoperimetric constant of a product. 相似文献
52.
53.
R.S. Kraußhar 《Journal of Mathematical Analysis and Applications》2007,325(1):359-376
In this paper we study Clifford and harmonic analysis on some examples of conformal flat manifolds that have a spinor structure, or more generally, at least a pin structure. The examples treated here are manifolds that can be parametrized by U/Γ where U is a subdomain of either Sn or Rn and Γ is a Kleinian group acting discontinuously on U. The examples studied here include RPn and the Hopf manifolds S1×Sn−1. Also some hyperbolic manifolds will be treated. Special kinds of Clifford-analytic automorphic forms associated to the different choices of Γ are used to construct explicit Cauchy kernels, Cauchy integral formulas, Green's kernels and formulas together with Hardy spaces and Plemelj projection operators for Lp spaces of hypersurfaces lying in these manifolds. 相似文献
54.
We prove equivalence of the definitions by the author and by Korevaar and Schoen of the Sobolev classes of mappings of a domain of an arithmetic n-dimensional space to a metric space. 相似文献
55.
T. Domínguez Benavides 《Journal of Mathematical Analysis and Applications》2004,291(1):100-108
Let X be a Banach space whose characteristic of noncompact convexity is less than 1 and satisfies the nonstrict Opial condition. Let C be a bounded closed convex subset of X, KC(X) the family of all compact convex subsets of X and T a nonexpansive mapping from C into KC(X) with bounded range. We prove that T has a fixed point. The nonstrict Opial condition can be removed if, in addition, T is an 1-χ-contractive mapping. 相似文献
56.
Jing-Hui Qiu 《Journal of Mathematical Analysis and Applications》2004,292(2):459-469
A weaker Mackey topology, infra-Mackey topology, is introduced. For an infra-Mackey space, dual local quasi-completeness, c0-quasi-barrelledness, Ruess' property (quasi-L) and C-quasi-barrelledness are equivalent to each other. Inspired by the definition of Mazur spaces, locally convex spaces are classified according to various conditions ensuring linear functionals continuous. In the classification, every class of special locally convex spaces is characterized by some completeness of the duals. From this, some new characterizations of quasi-barrelledness and barrelledness are given. 相似文献
57.
Let SB(X,Y) be the set of the bounded sublinear operators from a Banach space X into a Banach lattice Y. Consider π2(X,Y) the set of 2-summing sublinear operators. We study in this paper a variation of Grothendieck's theorem in the sublinear operators case. We prove under some conditions that every operator in SB(C(K),H) is in π2(C(K),H) for any compact K and any Hilbert H. In the noncommutative case the problem is still open. 相似文献
58.
59.
K-强凸空间的一些性质 总被引:4,自引:0,他引:4
结合Banach空间的Drop性,利用K维体积给出了K—强凸空间的一个新的定义,同时也给出了K—强光滑空间定义的K维体积表示,然后利用单位圆的切片证明了K—强凸空间是自反空间,进而证明了K—强凸空间与K—强光滑空间是一对对偶空间.最后利用Drop性的切片描述证明了K—强凸空间具有Drop性. 相似文献
60.
曾六川 《高校应用数学学报(英文版)》2003,18(3):283-286
Let(X,‖·‖ ) be a Banach space.Let K be a nonempty closed,convex subset of Xand T∶K→K.Assume that T is Lipschitzian,i.e.there exists L>0 such that‖ T(x) -T(y)‖≤ L‖ x -y‖for all x,y∈K.Withoutloss of generality,assume that L≥ 1 .Assume also that T is strictly pseudocontractive.According to[1 ] this may be statedas:there exists k∈ (0 ,1 ) such that‖ x -y‖≤‖ x -y + r[(I -T -k I) x -(I -T -k I) y]‖for all r>0 and all x,y∈ K.Throughout,let N denote the set of positive in… 相似文献