全文获取类型
收费全文 | 357347篇 |
免费 | 6692篇 |
国内免费 | 4937篇 |
专业分类
化学 | 173032篇 |
晶体学 | 5303篇 |
力学 | 20800篇 |
综合类 | 325篇 |
数学 | 50822篇 |
物理学 | 118694篇 |
出版年
2021年 | 4675篇 |
2020年 | 5145篇 |
2019年 | 5924篇 |
2018年 | 7911篇 |
2017年 | 7955篇 |
2016年 | 10042篇 |
2015年 | 5379篇 |
2014年 | 9268篇 |
2013年 | 15457篇 |
2012年 | 13765篇 |
2011年 | 15505篇 |
2010年 | 12765篇 |
2009年 | 12869篇 |
2008年 | 14349篇 |
2007年 | 13880篇 |
2006年 | 12528篇 |
2005年 | 10810篇 |
2004年 | 10266篇 |
2003年 | 9417篇 |
2002年 | 9741篇 |
2001年 | 9216篇 |
2000年 | 7292篇 |
1999年 | 5601篇 |
1998年 | 5282篇 |
1997年 | 4962篇 |
1996年 | 4568篇 |
1995年 | 4005篇 |
1994年 | 4099篇 |
1993年 | 4084篇 |
1992年 | 4003篇 |
1991年 | 4404篇 |
1990年 | 4387篇 |
1989年 | 4314篇 |
1988年 | 4032篇 |
1987年 | 4083篇 |
1986年 | 3748篇 |
1985年 | 4309篇 |
1984年 | 4517篇 |
1983年 | 3894篇 |
1982年 | 4058篇 |
1981年 | 3699篇 |
1980年 | 3458篇 |
1979年 | 3997篇 |
1978年 | 4077篇 |
1977年 | 4204篇 |
1976年 | 4364篇 |
1975年 | 4062篇 |
1974年 | 3967篇 |
1973年 | 4087篇 |
1972年 | 3545篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
Guofen Yu Yuanci Gao Shenggang Liu Wenxiang Wang Jin Wu 《International Journal of Infrared and Millimeter Waves》2002,23(8):1261-1269
Analysis of the field distributions in a single biological cell under electromagnetic wave is given. With Debye approximation, the dielectric relaxation of each part of the cell, including the extracellular and cellular media, the cell membrane and the nuclear membrane, was taken into account. Making use of some typical parameters for a cell, the voltage across nuclear and cytoplasma membranes under electromagnetic waves are calculated up to millimeter wave frequency range. The calculated result indicates that it is unlikely to generate electroporation by present available millimeter wave sources. 相似文献
72.
K. Batra V. Prasad M. Mohan 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,20(2):191-198
The scattering of heavy ion with a multilevel Rydberg atom in the presence of an electromagnetic field is studied. The interaction
of Rydberg atom and the e.m field is explored using non-perturbative quasi-energy technique. Although the results are presented
for selected excitations but in actual calculations we have included many levels of the atom. The effect of various parameters
are shown on collisional excitation process. As an illustration detailed calculations are performed for the inelastic proton-Na
Rydberg atom collision accompanied by the transfer of photons and the effects of dressing due to the field are considered.
The emphasis of the present work is on collision induced transitions especially the case that involves change of orbital as
well as principal quantum number.
Received 26 December 2001 / Received in final form 8 April 2002 Published online 19 July 2002 相似文献
73.
A. I. Bril' V. P. Kabashnikov N. V. Kuz'mina Yu. V. Khodyko 《Journal of Applied Spectroscopy》1991,55(3):934-939
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 55, No. 3, pp. 478–484, September, 1991. 相似文献
74.
V. K. Malyutenko A. I. Liptuga V. A. Botte V. I. Chernyakhovskii 《Journal of Applied Spectroscopy》1991,55(4):1024-1028
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 55, No. 4, pp. 624–629, October, 1991. 相似文献
75.
V. V. Tokarchuk 《Journal of Applied Mathematics and Mechanics》1989,53(6):708-715
The Langevin dynamics and fluctuational-dissipative relationships for the hydrodynamic fluctuations for systems which are described in the third Barnett order with respect to the gradients of the hydrodynamic variables are generalized on the basis of a kinetic approach. 相似文献
76.
77.
78.
V. I. Korobov 《Few-Body Systems》2002,31(2-4):133-138
In this contribution we consider a phenomenon of metastable states in antiprotonic helium atoms, precise spectroscopy of
these states and a present-day study of the electromagnetic properties of antiprotons.
Received October 16, 2001; accepted for publication November 13, 2001 相似文献
79.
The effect of hydrogen on the photoluminescence and planar conductivity of GaAs/InGaAs quantum-well heterostructures with an island Pd layer at the anodically oxidized surface was studied. Unlike continuous deposited Pd layers, island layers do not cause the formation of defects in the GaAs surface region and yet the Pd layer maintains high catalytic activity with respect to hydrogen. It is found that the thermal treatment of such a structure in a hydrogen atmosphere causes atomic-hydrogen passivation of the defects in quantum wells. Studies of the characteristics of planar photoresistors with an island Pd layer acting as hydrogen sensors show that their hydrogen detectivity is approximately two orders of magnitude higher than that of diode structures with continuous Pd layers. 相似文献
80.
V. Čápek 《Czechoslovak Journal of Physics》1991,41(10):975-989
A review of ideas leading to full rejection of any finite or partially-infinite order kinetic equation linearized in external field is given on grounds of the time-convolution Generalized Master Equations (GME). By two examples (two-level and band conduction problem), it is shown how standard kinetic equations result from GME in the lowest order approximations which obscure, however, a direct correspondence with the Kubo linear response theory. Without approximations, on the other hand, the rigorous approach is shown to be fully equivalent with the Kubo results. It is argued and illustrated that usual technical simplicity and seeming physical lucidity of standard theories (connected with the presence of field-independent transfer or scattering rates in the fielddependent linearized theory) are just owing to structural features which are solely due to the lowest order approximations involved. These features (i.e. also the possibility of standard physical interpretation of kinetic phenomena) are proved to disappear completely as far as the theory goes properly to higher orders. 相似文献