全文获取类型
收费全文 | 5413篇 |
免费 | 485篇 |
国内免费 | 373篇 |
专业分类
化学 | 701篇 |
晶体学 | 29篇 |
力学 | 464篇 |
综合类 | 50篇 |
数学 | 1194篇 |
物理学 | 1388篇 |
综合类 | 2445篇 |
出版年
2024年 | 7篇 |
2023年 | 42篇 |
2022年 | 62篇 |
2021年 | 96篇 |
2020年 | 111篇 |
2019年 | 130篇 |
2018年 | 126篇 |
2017年 | 147篇 |
2016年 | 154篇 |
2015年 | 150篇 |
2014年 | 200篇 |
2013年 | 347篇 |
2012年 | 243篇 |
2011年 | 252篇 |
2010年 | 183篇 |
2009年 | 281篇 |
2008年 | 218篇 |
2007年 | 290篇 |
2006年 | 319篇 |
2005年 | 251篇 |
2004年 | 239篇 |
2003年 | 254篇 |
2002年 | 234篇 |
2001年 | 208篇 |
2000年 | 212篇 |
1999年 | 175篇 |
1998年 | 139篇 |
1997年 | 138篇 |
1996年 | 112篇 |
1995年 | 114篇 |
1994年 | 98篇 |
1993年 | 108篇 |
1992年 | 84篇 |
1991年 | 83篇 |
1990年 | 83篇 |
1989年 | 71篇 |
1988年 | 79篇 |
1987年 | 50篇 |
1986年 | 35篇 |
1985年 | 27篇 |
1984年 | 20篇 |
1983年 | 11篇 |
1982年 | 20篇 |
1981年 | 13篇 |
1980年 | 7篇 |
1979年 | 8篇 |
1978年 | 16篇 |
1977年 | 5篇 |
1976年 | 5篇 |
1973年 | 6篇 |
排序方式: 共有6271条查询结果,搜索用时 31 毫秒
21.
E. Hatta H. Hosoi H. Akiyama T. Ishii K. Mukasa 《The European Physical Journal B - Condensed Matter and Complex Systems》1998,2(3):347-349
We have observed a remarkable two-armed spiral in the collapse process of a floating monolayer at the air-water interface
by phase contrast microscopy. This demonstrates that the floating monolayer as a form of soft condensed matter reorganizes
itself due to a certain kind of macroscopic or collective behavior of molecules as it collapses. This pattern formation is
caused by the breakdown of a critical dynamical balance between the deformation of solid domain and the applied surface pressure.
The fragility as well as the flexibility of the floating monolayer can be associated with the observed pattern growth. There
are also observed interesting, periodically arranged collections of molecules in numerous collapsed regions.
Received: 8 July 1997 / Accepted: 4 November 1997 相似文献
22.
Ricardo García-Pelayo Iván Salazar William C. Schieve 《Journal of statistical physics》1993,72(1-2):167-187
An analytically solvable model for sand avalanches of noninteracting grains of sand, based on the Chapman-Kolmogorov equations, is presented. For a single avalanche, distributions of lifetimes, sizes of overflows and avalanches, and correlation functions are calculated. Some of these are exponentials, some are power laws. Spatially homogeneous distributions of avalanches are also studied. Computer simulations of avalanches of interacting grains of sand are compared to the solutions to the Chapman-Kolmogorov equations. We find that within the range of parameters explored in the simulation, the approximation of noninteracting grains of sand is a good one. 相似文献
23.
李永青 《福建师范大学学报(自然科学版)》1995,11(3):16-20
讨论一个非线性椭圆特征问题,减弱了原有结果中的一个条件而得到同样的结果,并讨论了参数小于λ1的情形。 相似文献
24.
25.
Dirichlet boundary value problems for perturbed second-order differential equations on a half line are investigated in this paper. The methods mainly depend on the calculus of variations to the classical functionals. Sufficient conditions are obtained for the existence of the solutions. 相似文献
26.
27.
P. Mun F. C. Fonseca R. Muccillo R. F. Jardim 《Physica C: Superconductivity and its Applications》2003,390(4):363-373
A systematic study of the magnetic hysteresis in transport properties of polycrystalline YBa2Cu3O7−δ–Ag compounds has been made based on two kinds of measurements at 77 K and under applied magnetic fields up to 30 mT: critical current density Jc(Ba) and magnetoresistance R(Ba). The R(Ba) curves show a minimum in their decreasing branch occurring at B=Bmin which was found to be both the excitation current Iex and the maximum applied magnetic field Bam dependent. In addition, for a certain value of Bam>5 mT, we have observed that Bmin increases with increasing Iex and reaches a saturation value. The Jc(Ba) curves show a maximum in decreasing applied magnetic fields occurring at B=Bmax. We have also found that Bmax increases with increasing Bam and reaches a saturation value. The minimum in the R(Ba) and the maximum in Jc(Ba) curves were found to be related to the trapped flux within the grains. All the experimental results are discussed within the context of the flux dynamics and transport mechanisms in these high-Tc materials. 相似文献
28.
一类幂数列的单调性 总被引:1,自引:1,他引:0
桂曙光 《合肥工业大学学报(自然科学版)》2002,25(3):477-479
关于一类幂数列的单调性已经有了一些特殊结果 ,而该文以导数为工具 ,通过对幂指型函数图象特征的讨论 ,构造出一个特殊的数列 { bk} ,解决了该类幂数列的单调性 ,得到了 2个有趣的结果。当 l 相似文献
29.
Details are given of a new method allowing an exact calculation of the spontaneous magnetization in the corner as well as along the edge at an arbitrary distance of the corner for a rectangular planar Ising ferromagnet. 相似文献
30.
蔡海榕 《杭州师范学院学报(社会科学版)》2003,1(3):70-74
当代西方学者正在深入讨论现代性给知识分子生活带来的深刻变化。在现代性危机状态下,反思批判性知识分子的历史使命,这对中国知识分子在现代化进程中如何履行应有的职责,不乏启发意义。 相似文献