全文获取类型
收费全文 | 30378篇 |
免费 | 278篇 |
国内免费 | 319篇 |
专业分类
化学 | 10733篇 |
晶体学 | 271篇 |
力学 | 1419篇 |
综合类 | 53篇 |
数学 | 9025篇 |
物理学 | 9474篇 |
出版年
2021年 | 32篇 |
2020年 | 31篇 |
2019年 | 34篇 |
2018年 | 1224篇 |
2017年 | 1459篇 |
2016年 | 725篇 |
2015年 | 561篇 |
2014年 | 483篇 |
2013年 | 691篇 |
2012年 | 3131篇 |
2011年 | 2485篇 |
2010年 | 1942篇 |
2009年 | 1651篇 |
2008年 | 586篇 |
2007年 | 699篇 |
2006年 | 717篇 |
2005年 | 4523篇 |
2004年 | 4035篇 |
2003年 | 2503篇 |
2002年 | 656篇 |
2001年 | 447篇 |
2000年 | 155篇 |
1999年 | 211篇 |
1998年 | 134篇 |
1997年 | 75篇 |
1996年 | 47篇 |
1995年 | 45篇 |
1994年 | 43篇 |
1992年 | 171篇 |
1991年 | 154篇 |
1990年 | 136篇 |
1989年 | 110篇 |
1988年 | 100篇 |
1987年 | 56篇 |
1986年 | 41篇 |
1985年 | 38篇 |
1984年 | 29篇 |
1983年 | 28篇 |
1979年 | 31篇 |
1978年 | 28篇 |
1976年 | 80篇 |
1975年 | 39篇 |
1974年 | 40篇 |
1973年 | 48篇 |
1972年 | 39篇 |
1970年 | 34篇 |
1969年 | 37篇 |
1968年 | 35篇 |
1967年 | 30篇 |
1966年 | 37篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
In the paper we indicate an error made in the proof of the main result of the paper [M.A. Darwish, On quadratic integral equation of fractional orders, J. Math. Anal. Appl. 311 (2005) 112-119]. Moreover, we provide correct proof of a slightly modified version of the mentioned result. The main tool used in our proof is the technique associated with the Hausdorff measure of noncompactness. 相似文献
62.
C. Bréchignac Ph. Cahuzac F. Carlier C. Colliex M. de Frutos N. Kébaïli J. Le Roux A. Masson B. Yoon 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,24(1-3):265-268
We studied shape relaxation of nano-fractal islands,
during annealing, after their growth from antimony cluster
deposition on graphite surface. Annealing at
180°C shows evidence of an increase
of the fractal branch width with time followed by branch
fragmentation, without changing the fractal dimension. The time
evolution of the width of the arm suggests the surface
self-diffusion mechanism as the main relaxation process. With
Monte Carlo simulations, we confirmed the observed behavior.
Comparison is done with our previous results on fragmentation of
nano-fractal silver islands when impurity added to the incident
cluster promotes rapid fragmentation by surface self-diffusion
enhancement [1]. 相似文献
63.
64.
In this paper we deal with nonlinear second-order boundary value problems with impulses. The impulsive functions depend implicitly on the different considered variables and the boundary value conditions are nonlinear. In both cases functional dependence on the solution is allowed. The existence results follow from the existence of a pair of well-ordered lower and upper solutions. 相似文献
65.
We study linear dynamical systems with multidimensional time in Banach spaces. Using Taylor functional calculus we prove that under additional assumptions hyperbolic systems have shadowing property. 相似文献
66.
S?awomir Solecki 《Topology and its Applications》2007,154(12):2462-2464
Let I0 be the σ-ideal of subsets of a Polish group generated by Borel sets which have perfectly many pairwise disjoint translates. We prove that a Fubini-type theorem holds between I0 and the σ-ideals of Haar measure zero sets and of meager sets. We use this result to give a simple proof of a generalization of a theorem of Balcerzak-Ros?anowski-Shelah stating that I0 on N2 strongly violates the countable chain condition. 相似文献
67.
68.
R. Knizikevi?ius 《Applied Surface Science》2006,253(3):1581-1583
The ion-beam-assisted etching of silicon in Cl2 environment is considered. The theoretically calculated dependences of silicon etching rate on the flux of Cl2 molecules at different ion current densities are compared with experimentally measured. The composition of the adsorbed layer is determined. It is found that SiCl2 molecules prevail in the adsorbed layer. The reciprocal of relative concentration of SiCl2 molecules in the adsorbed layer linearly depends on the ion-to-neutral flux ratio. 相似文献
69.
Wei-nan E Ping-bing Ming 《应用数学学报(英文版)》2007,23(4):529-550
We study continuum and atomistic models for the elastodynamics of crystalline solids at zerotemperature.We establish sharp criterion for the regime of validity of the nonlinear elastic wave equationsderived from the well-known Cauchy-Born rule. 相似文献
70.
M. A. Rizzutto N. Added M. H. Tabacniks F. R. Espinoza-Qui?ones S. M. Palacio R. M. Galante R. M. Galante N. Rossi R. A. Welter A. N. Módenes 《Journal of Radioanalytical and Nuclear Chemistry》2006,269(3):727-731
Summary Kulcsszavak (angolul, ha nem azonos az elozovel) 相似文献