全文获取类型
收费全文 | 13819篇 |
免费 | 1129篇 |
国内免费 | 1646篇 |
专业分类
化学 | 722篇 |
晶体学 | 16篇 |
力学 | 704篇 |
综合类 | 325篇 |
数学 | 12842篇 |
物理学 | 1985篇 |
出版年
2024年 | 16篇 |
2023年 | 145篇 |
2022年 | 123篇 |
2021年 | 211篇 |
2020年 | 244篇 |
2019年 | 314篇 |
2018年 | 292篇 |
2017年 | 354篇 |
2016年 | 371篇 |
2015年 | 290篇 |
2014年 | 588篇 |
2013年 | 905篇 |
2012年 | 568篇 |
2011年 | 743篇 |
2010年 | 712篇 |
2009年 | 955篇 |
2008年 | 1015篇 |
2007年 | 1099篇 |
2006年 | 914篇 |
2005年 | 840篇 |
2004年 | 650篇 |
2003年 | 706篇 |
2002年 | 612篇 |
2001年 | 508篇 |
2000年 | 596篇 |
1999年 | 489篇 |
1998年 | 465篇 |
1997年 | 412篇 |
1996年 | 281篇 |
1995年 | 165篇 |
1994年 | 170篇 |
1993年 | 113篇 |
1992年 | 90篇 |
1991年 | 78篇 |
1990年 | 64篇 |
1989年 | 35篇 |
1988年 | 47篇 |
1987年 | 29篇 |
1986年 | 23篇 |
1985年 | 50篇 |
1984年 | 46篇 |
1983年 | 21篇 |
1982年 | 42篇 |
1981年 | 30篇 |
1980年 | 32篇 |
1979年 | 31篇 |
1978年 | 30篇 |
1977年 | 25篇 |
1976年 | 14篇 |
1974年 | 10篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
121.
§ 1. Introduction Anecessaryandsufficientconditionandasufficientconditiontoensurethataset valuedmappingandasingle valuedmappinginacompletemetricspaceandacompleteconvexmetricspacehavingacommonfixedpointarerespectivelygivenin [1 ] .Meanwhilethemainresultsin[2 ]— [5]areimprovedandextendedin [1 ] .Inthispaper ,theexistenceatcommonfixedpointsoftwoset valuedmappingandasing valuedmappingwerestudied ,andthecorrespond ingresultsin [1 ]— [5]wereextendedandimproved .Let(X ,d)beanon emptymetricspa… 相似文献
122.
Sylvia Pulmannová 《International Journal of Theoretical Physics》2003,42(5):907-919
Tensor products of quantum logics and effect algebras with some known problems are reviewed. It is noticed that although tensor products of effect algebras having at least one state exist, in the category of complex Hilbert space effect algebras similar problems as with tensor products of projection lattices occur. Nevertheless, if one of the two coupled physical systems is classical, tensor product exists and can be considered as a Boolean power. Some applications of tensor products (in the form of Boolean powers) to quantum measurements are reviewed. 相似文献
123.
124.
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
125.
Regularity of Harmonic Functions in Cheeger-Type Sobolev Spaces 总被引:3,自引:0,他引:3
We give a geometric approach to the study of the regularity of harmonic functions in Cheeger-type Sobolev spaces, and prove the Hölder continuity of such functions. In the proof, we give a definition of an upper curvature bound of the unit sphere of a Banach space, which seems to be of independent interest. 相似文献
126.
M. D. Guay 《Acta Mathematica Hungarica》2004,105(3):241-248
Axioms are given for a preconvexity space and certain consequences obtained. In particular, it is shown that in a very natural
way, a preconvexity on a space yields an abstract convexity space in much the same manner as a proximity yields a topological
space.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
127.
WEIERSTRASS REPRESENTATION FORSURFACES WITH PRESCRIBED NORMALGAUSS MAP AND GAUSS CURVATURE IN H~3 下载免费PDF全文
SHI Shuguo 《数学年刊B辑(英文版)》2004,25(4):567-586
The author obtains a Weierstrass representation for surfaces with prescribed normal Gauss map and Gauss curvature in H3. A differential equation about the hyperbolic Gauss map is also obtained, which characterizes the relation among the hyperbolic Gauss map, the normal Gauss map and Gauss curvature. The author discusses the harmonicity of the normal Gauss map and the hyperbolic Gauss map from surface with constant Gauss curvature in H3 to S2 with certain altered conformal metric. Finally, the author considers the surface whose normal Gauss map is conformal and derives a completely nonlinear differential equation of second order which graph must satisfy. 相似文献
128.
几何凸函数与琴生型不等式 总被引:20,自引:3,他引:17
吴善和 《数学的实践与认识》2004,34(2):155-163
给出几何凸函数的定义以及判定几何凸函数的方法 ,建立关于几何凸函数的琴生型不等式 ,最后给出它的应用 ,包括改进一些已知不等式和建立一些新不等式 . 相似文献
129.
PURE STATE APPROACH TO C(x)_αZ_nLIBINGREN;LINQING(InstituteofMathematics,AcademiaSinica,Beijing100080,China.Projectsupportedbyth?.. 相似文献
130.
Joe Warren Scott Schaefer Anil N. Hirani Mathieu Desbrun 《Advances in Computational Mathematics》2007,27(3):319-338
In this paper we provide an extension of barycentric coordinates from simplices to arbitrary convex sets. Barycentric coordinates
over convex 2D polygons have found numerous applications in various fields as they allow smooth interpolation of data located
on vertices. However, no explicit formulation valid for arbitrary convex polytopes has been proposed to extend this interpolation
in higher dimensions. Moreover, there has been no attempt to extend these functions into the continuous domain, where barycentric
coordinates are related to Green’s functions and construct functions that satisfy a boundary value problem. First, we review
the properties and construction of barycentric coordinates in the discrete domain for convex polytopes. Next, we show how
these concepts extend into the continuous domain to yield barycentric coordinates for continuous functions. We then provide
a proof that our functions satisfy all the desirable properties of barycentric coordinates in arbitrary dimensions. Finally,
we provide an example of constructing such barycentric functions over regions bounded by parametric curves and show how they
can be used to perform freeform deformations.
相似文献