全文获取类型
收费全文 | 6370篇 |
免费 | 147篇 |
国内免费 | 15篇 |
专业分类
化学 | 4465篇 |
晶体学 | 17篇 |
力学 | 109篇 |
数学 | 889篇 |
物理学 | 1052篇 |
出版年
2020年 | 51篇 |
2019年 | 45篇 |
2016年 | 111篇 |
2015年 | 81篇 |
2014年 | 119篇 |
2013年 | 243篇 |
2012年 | 208篇 |
2011年 | 239篇 |
2010年 | 158篇 |
2009年 | 137篇 |
2008年 | 202篇 |
2007年 | 203篇 |
2006年 | 217篇 |
2005年 | 194篇 |
2004年 | 197篇 |
2003年 | 140篇 |
2002年 | 163篇 |
2001年 | 123篇 |
2000年 | 93篇 |
1999年 | 102篇 |
1998年 | 105篇 |
1997年 | 114篇 |
1996年 | 123篇 |
1995年 | 108篇 |
1994年 | 112篇 |
1993年 | 116篇 |
1992年 | 117篇 |
1991年 | 95篇 |
1990年 | 102篇 |
1989年 | 108篇 |
1988年 | 100篇 |
1987年 | 116篇 |
1986年 | 128篇 |
1985年 | 140篇 |
1984年 | 112篇 |
1983年 | 99篇 |
1982年 | 87篇 |
1981年 | 95篇 |
1980年 | 119篇 |
1979年 | 76篇 |
1978年 | 103篇 |
1977年 | 90篇 |
1976年 | 89篇 |
1975年 | 57篇 |
1974年 | 80篇 |
1973年 | 80篇 |
1972年 | 65篇 |
1971年 | 55篇 |
1970年 | 66篇 |
1967年 | 44篇 |
排序方式: 共有6532条查询结果,搜索用时 15 毫秒
1.
Cavitation erosion is caused in solids exposed to strong pressure waves developing in an adjacent fluid field. The knowledge of the transient distribution of stresses in the solid is important to understand the cause of damaging by comparisons with breaking points of the material. The modeling of this problem requires the coupling of the models for the fluid and the solid. For this purpose, we use a strategy based on the solution of coupled Riemann problems that has been originally developed for the coupling of 2 fluids. This concept is exemplified for the coupling of a linear elastic structure with an ideal gas. The coupling procedure relies on the solution of a nonlinear equation. Existence and uniqueness of the solution is proven. The coupling conditions are validated by means of quasi‐1D problems for which an explicit solution can be determined. For a more realistic scenario, a 2D application is considered where in a compressible single fluid, a hot gas bubble at low pressure collapses in a cold gas at high pressure near an adjacent structure. 相似文献
2.
3.
An effective residual interaction between particles and holes for shell model calculations around 208Pb, derived from the interaction between free nucleons, is compared with the measured properties of proton-hole neutron states
in 208Tl and the interaction between proton holes is adjusted to newly measured level energies in 206Hg. These interaction elements are particularly relevant for neutron-rich nuclei. The adjustment of two mixing elements reproduces
the known γ-decay data in 208Tl.
Received: 2 April 2002 / Accepted: 2 May 2002 相似文献
4.
Gerhard Rein 《Mathematical Methods in the Applied Sciences》1992,15(5):365-374
We consider a collisionless plasma, which consists of electrons and positively charged ions and is confined to a bounded domain in ?3. The distribution functions of the particles are assumed to satisfy specular reflections on the boundary of the domain and the boundary is assumed to be perfectly conducting. We establish the existence of stationary plasmas in the non-relativistic, electrostatic case described by the Vlasov–Poisson system as well as in the relativistic, electrodynamic case described by the relativistic Vlasov–Maxwell system. 相似文献
5.
Using topological methods we give a proof that the free product of two strict subgroup separable groups with infinite cyclic amalgamation is subgroup separable. 相似文献
6.
Stefan A. Maier 《Optical and Quantum Electronics》2006,38(1-3):257-267
The controlled squeezing of electromagnetic energy into nanometric volumes via surface plasmon-polariton excitations in plasmonic nanoresonators is analyzed using the concept of an effective electromagnetic mode volume V eff, while taking careful account of the plasmon-polariton dispersion and the electromagnetic energy stored in the metal. Together with the quality factor Q of the cavity resonance, this enables a comparison with dielectric optical cavities, where V eff is limited by diffraction. For a Fabry–Perot type planar metallic cavity, a one-dimensional analytic model as well as a three-dimensional finite-difference time-domain simulation reveal that V eff is not bounded by diffraction, and that Q/V eff increases for decreasing cavity size. In this picture, matter–plasmon interactions can be quantified in terms of Q and V eff, and a resonant cavity model for the enhancement of spontaneous Raman scattering is presented. 相似文献
7.
8.
9.
Gerhard Lessner 《General Relativity and Gravitation》2004,36(5):1241-1242
10.