全文获取类型
收费全文 | 11536篇 |
免费 | 998篇 |
国内免费 | 1421篇 |
专业分类
化学 | 716篇 |
晶体学 | 16篇 |
力学 | 651篇 |
综合类 | 294篇 |
数学 | 10270篇 |
物理学 | 2008篇 |
出版年
2024年 | 18篇 |
2023年 | 133篇 |
2022年 | 131篇 |
2021年 | 187篇 |
2020年 | 215篇 |
2019年 | 288篇 |
2018年 | 259篇 |
2017年 | 300篇 |
2016年 | 315篇 |
2015年 | 247篇 |
2014年 | 513篇 |
2013年 | 813篇 |
2012年 | 453篇 |
2011年 | 659篇 |
2010年 | 605篇 |
2009年 | 812篇 |
2008年 | 903篇 |
2007年 | 941篇 |
2006年 | 757篇 |
2005年 | 711篇 |
2004年 | 528篇 |
2003年 | 611篇 |
2002年 | 524篇 |
2001年 | 413篇 |
2000年 | 463篇 |
1999年 | 409篇 |
1998年 | 389篇 |
1997年 | 304篇 |
1996年 | 226篇 |
1995年 | 123篇 |
1994年 | 129篇 |
1993年 | 77篇 |
1992年 | 57篇 |
1991年 | 54篇 |
1990年 | 42篇 |
1989年 | 28篇 |
1988年 | 33篇 |
1987年 | 20篇 |
1986年 | 16篇 |
1985年 | 38篇 |
1984年 | 34篇 |
1983年 | 16篇 |
1982年 | 31篇 |
1981年 | 17篇 |
1980年 | 24篇 |
1979年 | 19篇 |
1978年 | 15篇 |
1977年 | 16篇 |
1976年 | 10篇 |
1936年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 93 毫秒
91.
Durand William A.Pham Ngoc Dinh 《Journal of Mathematical Analysis and Applications》2003,282(1):95-106
An electromagnetic diffraction problem in a wedge shaped region is reduced to a system of coupled functional difference equations by means of Sommerfeld integrals and Malyuzhinets theorem. By introducing an integral operator it is shown that the solutions of this system of functional equations can be defined in terms of integral representations whose kernels are solutions of a singular integral equation of Cauchy-Carleman type for which an explicit solution is given. 相似文献
92.
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
93.
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
94.
PURE STATE APPROACH TO C(x)_αZ_nLIBINGREN;LINQING(InstituteofMathematics,AcademiaSinica,Beijing100080,China.Projectsupportedbyth?.. 相似文献
95.
We prove that a locally compact ANR-space X is a Q-manifold if and only if it has the Disjoint Disk Property (DDP), all points of X are homological Z
∞-points and X has the countable-dimensional approximation property (cd-AP), which means that each map f: K → X of a compact polyhedron can be approximated by a map with the countable-dimensional image. As an application we prove that
a space X with DDP and cd-AP is a Q-manifold if some finite power of X is a Q-manifold. If some finite power of a space X with cd-AP is a Q-manifold, then X
2 and X × [0, 1] are Q-manifolds as well. We construct a countable family χ of spaces with DDP and cd-AP such that no space X ∈ χ is homeomorphic to the Hilbert cube Q whereas the product X × Y of any different spaces X, Y ∈ χ is homeomorphic to Q. We also show that no uncountable family χ with such properties exists.
This work was supported by the Slovenian-Ukrainian (Grant No. SLO-UKR 04-06/07) 相似文献
96.
Florence Newberger 《Geometriae Dedicata》2003,97(1):215-249
The goal of this paper is to provide a tool, the Global Measure Formula, that will facilitate the study of the limit set of discrete geometrically finite groups of isometries of the rank one symmetric spaces. We consider the shadow of a ball from a fixed reference point onto the boundary, and prove a formula that describes the measure of the shadow in terms of the center of the shadowed ball, generalizing a result from real hyperbolic geometry. 相似文献
97.
98.
By introducing an imaginary space transform curvature ρs, a complex space called Riemannian space is constructed, in which the light propagating in free space has the trajectory
of straight line while propagating. Moreover, this curvature couples with that of the wave front of the paraxial beam ρw, and therefore a complex curvature ρc is constructed, which can be employed to investigate the behavior of the light transmission and to generalize the ABCD law.
Project supported by the National Hi-Tech Inertial Confinement Fusion Committee, the Guangdong Natural Science Foundation
the Postdoctoral Foundation of Guangdong and National Postdoctoral Foundation of China. 相似文献
99.
A new method of using time-averaged digital speckle pattern interferometry for the quantitative measurement of vibration amplitude was developed. Signal processing techniques especially the Hilbert transformation for quantitative evaluation of the Bessel fringes obtained in time-averaged digital speckle pattern interferometry were explored. The quadrature signal after Hilbert transformation is equivalent to a 90° phase-shifted interferogram for a monotonically increasing or decreasing phase function. An algorithm was developed for Bessel fringe contrast enhancement and phase extraction. The techniques were tested numerically and experimentally. Sub-fringe quantification of the time-averaged vibration fringes is realised with the proposed method. Compared with the commonly used phase shift method which requires a minimum of two images for image processing, this method requires only one fringe pattern for data extraction. 相似文献
100.
本文主要研究了 Banach 空间上交换算子组的张量积以及 Banach 代数的张量积中交换元组的 Taylor 联合谱,推广了 Vasilescu,F.H.及 Wrobel,V.等人结果。 相似文献