全文获取类型
收费全文 | 10637篇 |
免费 | 1657篇 |
国内免费 | 1359篇 |
专业分类
化学 | 7701篇 |
晶体学 | 144篇 |
力学 | 530篇 |
综合类 | 77篇 |
数学 | 1266篇 |
物理学 | 3935篇 |
出版年
2024年 | 36篇 |
2023年 | 198篇 |
2022年 | 389篇 |
2021年 | 362篇 |
2020年 | 380篇 |
2019年 | 431篇 |
2018年 | 361篇 |
2017年 | 340篇 |
2016年 | 460篇 |
2015年 | 506篇 |
2014年 | 582篇 |
2013年 | 712篇 |
2012年 | 910篇 |
2011年 | 991篇 |
2010年 | 661篇 |
2009年 | 639篇 |
2008年 | 701篇 |
2007年 | 639篇 |
2006年 | 612篇 |
2005年 | 478篇 |
2004年 | 374篇 |
2003年 | 334篇 |
2002年 | 285篇 |
2001年 | 257篇 |
2000年 | 267篇 |
1999年 | 256篇 |
1998年 | 196篇 |
1997年 | 171篇 |
1996年 | 173篇 |
1995年 | 157篇 |
1994年 | 161篇 |
1993年 | 111篇 |
1992年 | 114篇 |
1991年 | 105篇 |
1990年 | 74篇 |
1989年 | 43篇 |
1988年 | 39篇 |
1987年 | 34篇 |
1986年 | 25篇 |
1985年 | 23篇 |
1984年 | 13篇 |
1983年 | 24篇 |
1982年 | 7篇 |
1981年 | 4篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 3篇 |
1976年 | 2篇 |
1971年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
We consider concentrated vorticities for the Euler equation on a smooth domain in the form of supported on well-separated vortical domains , , of small diameters . A conformal mapping framework is set up to study this free boundary problem with being part of unknowns. For any given vorticities and small , through a perturbation approach, we obtain such piecewise constant steady vortex patches as well as piecewise smooth Lipschitz steady vorticities, both concentrated near non-degenerate critical configurations of the Kirchhoff–Routh Hamiltonian function. When vortex patch evolution is considered as the boundary dynamics of , through an invariant subspace decomposition, it is also proved that the spectral/linear stability of such steady vortex patches is largely determined by that of the 2N-dimensional linearized point vortex dynamics, while the motion is highly oscillatory in the 2N-codim directions corresponding to the vortical domain shapes. 相似文献
2.
3.
What Is Its Real Existing Form?——Theoretical and Experimental Studies on 2-Mercaptobenzothiazole 总被引:1,自引:0,他引:1
1 INTRODUCTION The study of heterocyclic molecules with aroma- tic rings and their absorptions on metals is of con- siderable importance from both theoretical and te- chnological points of view. These molecules are in- teresting because of their applications as corrosion inhibitors and flotation collectors, and their abilities to form self-assembly layers[1]. 2-Mercaptobenzo- thiazole (C7H5NS2, in the following MBT) is an important heterocyclic molecule, which can be used as corrosion … 相似文献
4.
A lithium(I) coordination polymer has been formed from LiClO4 and the 2,2′‐bipyrimidine (bpym) ligand in which each square pyramidal lithium(I) atom is coordinated in the basal plane by four nitrogen donor atoms derived from two bpym ligands and one water molecule at the apical position. These are connected into a layer structure via hydrogen‐bonding interactions involving the perchlorate anions. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
5.
曾六川 《高等学校计算数学学报(英文版)》2003,12(1)
The purpose of this paper is to investigate the problem of approximating fixed points of non-Lipschitizian asymptotically pseudocontractive mappings in an arbitrary real Banach space by the modified Ishikawa iterative sequences with errors. 相似文献
6.
7.
A Note on Topological Entropy of Maps 总被引:1,自引:0,他引:1
For a given collection of subsets of a compact metric space X which cover X,the entropies,hm(f)and hi(f),are introduced for a continuous map f of X to itseif. Also the concept of shadowing property with same end point (SPSEP for short) is introduced. The main results are,(1)H(f)≤hi(f)+hm(f)and,(2)h(f)=hm(f)whenever f has SPSEP,where h(f) is the topological entropy of f. Moreover,several corollaries are obtained. 相似文献
8.
利用指数二分性和泛函分析方法,我们研究了当未扰动系统不具有异宿流形的退化异宿分支.我们利用Melnikov型向量给出了系统在退化情形下的横截异宿轨道存在的充分条件. 相似文献
9.
10.
Pingan Zeng Jiaquan Liu Yuxia Guo 《Journal of Mathematical Analysis and Applications》2004,300(1):102-128
In this paper, by using the Morse index theory for strongly indefinite functionals developed in [Nonlinear Anal. TMA, in press], we compute precisely the critical groups at the origin and at infinity, respectively. The abstract theorems are used to study the existence (multiplicity) of nontrivial periodical solutions for asymptotically wave equation and beam equation with resonance both at infinity and at zero. 相似文献