全文获取类型
收费全文 | 87938篇 |
免费 | 888篇 |
国内免费 | 981篇 |
专业分类
化学 | 30724篇 |
晶体学 | 941篇 |
力学 | 7132篇 |
综合类 | 50篇 |
数学 | 32687篇 |
物理学 | 18273篇 |
出版年
2024年 | 103篇 |
2023年 | 219篇 |
2022年 | 292篇 |
2021年 | 386篇 |
2020年 | 443篇 |
2019年 | 405篇 |
2018年 | 10643篇 |
2017年 | 10433篇 |
2016年 | 6470篇 |
2015年 | 1220篇 |
2014年 | 751篇 |
2013年 | 971篇 |
2012年 | 4587篇 |
2011年 | 11287篇 |
2010年 | 6102篇 |
2009年 | 6514篇 |
2008年 | 7144篇 |
2007年 | 9276篇 |
2006年 | 698篇 |
2005年 | 1738篇 |
2004年 | 1818篇 |
2003年 | 2161篇 |
2002年 | 1221篇 |
2001年 | 433篇 |
2000年 | 470篇 |
1999年 | 308篇 |
1998年 | 338篇 |
1997年 | 258篇 |
1996年 | 305篇 |
1995年 | 254篇 |
1994年 | 195篇 |
1993年 | 183篇 |
1992年 | 133篇 |
1991年 | 138篇 |
1990年 | 123篇 |
1989年 | 96篇 |
1988年 | 104篇 |
1987年 | 94篇 |
1986年 | 93篇 |
1985年 | 78篇 |
1984年 | 67篇 |
1983年 | 43篇 |
1982年 | 61篇 |
1981年 | 49篇 |
1980年 | 54篇 |
1979年 | 52篇 |
1978年 | 44篇 |
1914年 | 45篇 |
1913年 | 41篇 |
1909年 | 41篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Antonio Strozzi 《Journal of Elasticity》2012,108(1):119-123
The solution of cylindrical problems is addressed. A series solution is considered of the biharmonic equation, in which the series terms of the stress function Φ are expressions based upon Legendre polynomials and logarithmically singular functions. An explicit form of a polynomial supplementing each logarithmically singular part of the series solution is obtained. 相似文献
52.
We consider the flow of a viscous incompressible fluid in a pipe when the boundary is a deformable shell of Naghdi type. We prove that the corresponding system of partial differential equations has a solution when the deformation of the shell is smooth and small enough. We propose an algorithm that uncouples the unknowns and prove its convergence. 相似文献
53.
We apply the recently improved version of the 0–1 test for chaos to real experimental time series of laser droplet generation process. In particular two marginal regimes of dripping are considered: spontaneous and forced dripping. The outcomes of the test reveal that both spontaneous and forced dripping time series can be characterized as chaotic, which coincides with the previous analysis based on nonlinear time series analysis. 相似文献
54.
55.
56.
57.
A review is given of the StandardSU(5) supergravity model. This model has passed an important check regarding unification of the electro-weak and the strong couplings using high precision LEP data. It is shown that for a significant domain of the parameter space the model also satisfies constraints on the SUSY spectrum from CDF and LEP, as well as proton stability and cosmological relic density constraints. 相似文献
58.
V. P. Silva Neto C. F. L. Vasconcelos M. R. M. L. Albuquerque A. G. D’Assunção 《Applied Physics A: Materials Science & Processing》2014,115(2):421-425
This work presents an analysis of the microstrip bandpass filter on metamaterial substrates. The filter is composed of two ring resonators with quarter-wavelength side-coupled sections. The filter input is provided, as well as the output port, using a quarter-wavelength side-coupled microstrip line section. Simulations by finite element method have been carried out to verify the effect of the metamaterial substrate properties on the filter performance, and to compare these results to those obtained considering isotropic substrate. 相似文献
59.
60.
We model and study the asymmetric long-range surface-plasmon waveguides using the finite-element method. We introduce two types of asymmetric structures and discuss their modal properties compared to traditional long-range surface-plasmon waveguides. Although the propagation distance is decreased, the energy-confinement capability is improved for asymmetric long-range waveguiding structures when the geometrical parameters are properly selected. Our simulation result offers guidance for tuning properties of plasmonic waveguides and providing ways for enhancing electromagnetic energy confinement in long-range surface-plasmon waveguides. 相似文献