全文获取类型
收费全文 | 324445篇 |
免费 | 2131篇 |
国内免费 | 885篇 |
专业分类
化学 | 136392篇 |
晶体学 | 4772篇 |
力学 | 18924篇 |
综合类 | 3篇 |
数学 | 69436篇 |
物理学 | 97934篇 |
出版年
2020年 | 1416篇 |
2019年 | 1575篇 |
2018年 | 18583篇 |
2017年 | 19203篇 |
2016年 | 11767篇 |
2015年 | 3413篇 |
2014年 | 3499篇 |
2013年 | 8084篇 |
2012年 | 12552篇 |
2011年 | 26403篇 |
2010年 | 16090篇 |
2009年 | 16518篇 |
2008年 | 21525篇 |
2007年 | 26409篇 |
2006年 | 6459篇 |
2005年 | 12994篇 |
2004年 | 9582篇 |
2003年 | 9474篇 |
2002年 | 6651篇 |
2001年 | 5578篇 |
2000年 | 4420篇 |
1999年 | 3137篇 |
1998年 | 2701篇 |
1997年 | 2532篇 |
1996年 | 2543篇 |
1995年 | 2314篇 |
1994年 | 2242篇 |
1993年 | 2156篇 |
1992年 | 2414篇 |
1991年 | 2369篇 |
1990年 | 2303篇 |
1989年 | 2241篇 |
1988年 | 2254篇 |
1987年 | 2253篇 |
1986年 | 2142篇 |
1985年 | 2757篇 |
1984年 | 2818篇 |
1983年 | 2510篇 |
1982年 | 2617篇 |
1981年 | 2427篇 |
1980年 | 2418篇 |
1979年 | 2565篇 |
1978年 | 2600篇 |
1977年 | 2434篇 |
1976年 | 2516篇 |
1975年 | 2425篇 |
1974年 | 2383篇 |
1973年 | 2607篇 |
1972年 | 1676篇 |
1971年 | 1368篇 |
排序方式: 共有10000条查询结果,搜索用时 7 毫秒
881.
V. A. Bednyakov 《Physics of Atomic Nuclei》2003,66(3):490-493
One can expect accessible lower bounds for the dark matter detection rate due to restrictions on masses of the SUSY partners. To explore this correlation, one needs a new-generation large-mass detector. The absolute lower bound for the detection rate can naturally be due to spin-dependent interaction. Aimed at detecting dark matter with sensitivity higher than 10?5 event/kg/d, an experiment should have a nonzero-spin target. Perhaps, it is best to create a GENIUS-like detector with both 73Ge (high spin) and 76Ge nuclei. 相似文献
882.
883.
884.
A pseudopotential depending on an effective core radius is proposed to study the binding energy, equation of state, ion-ion
interaction, phonon dispersion curves (q-space and r-space analysis), mode Grüneisen parameters and dynamical elastic constants
of some fcc f-shell metals La, Yb, Ce and Th. The contribution of the s-like electrons is calculated in the second-order perturbation
theory for the potential while d and f-like electron is taken into account by introducing repulsive short-range Born-Mayer
term. The parameter of the potential is evaluated by zero pressure condition. An excellent agreement between theoretical investigations
and experimental findings is achieved which confirms the present formalism 相似文献
885.
886.
887.
We discuss the concept of coarse wavelength-division multiplexing (CWDM) for metro networks. After reviewing the requirements on components such as lasers and fiber, we propose different architectures for a flexible upgrade of existing CWDM systems. 相似文献
888.
Makarov V. L. Khlobystov V. V. Kashpur E. F. Mikhal'chuk B. R. 《Ukrainian Mathematical Journal》2003,55(6):942-955
We construct an integral Newton-type interpolation polynomial with a continual set of nodes. This interpolant is unique and preserves an operator polynomial of the corresponding degree. 相似文献
889.
M. M. Glazov 《Physics of the Solid State》2003,45(6):1162-1165
A precession mechanism of spin relaxation of conduction electrons in a square quantum well is analyzed. The dependence of the spin relaxation time on the width of a quantum well and the height of its barriers is calculated under the assumption that the electron-electron collisions dominate over other processes of carrier scattering. 相似文献
890.
We study the half-space problem of the nonlinear Boltzmann equation, assigning the Dirichlet data for outgoing particles
at the boundary and a Maxwellian as the far field. We will show that the solvability of the problem changes with the Mach
number ℳ∞ of the far Maxwellian. If ℳ∞<−1, there exists a unique smooth solution connecting the Dirichlet data and the far Maxwellian for any Dirichlet data sufficiently
close to the far Maxwellian. Otherwise, such a solution exists only for the Dirichlet data satisfying certain admissible conditions.
The set of admissible Dirichlet data forms a smooth manifold of codimension 1 for the case −1<ℳ∞<0, 4 for 0<ℳ∞<1 and 5 for ℳ∞>1, respectively. We also show that the same is true for the linearized problem at the far Maxwellian, and the manifold is,
then, a hyperplane. The proof is essentially based on the macro-micro or hydrodynamics-kinetic decomposition of solutions
combined with an artificial damping term and a spatially exponential decay weight.
Received: 20 April 2002 / Accepted: 4 December 2002
Published online: 21 March 2003
Communicated by H.-T. Yau 相似文献