全文获取类型
收费全文 | 379239篇 |
免费 | 2677篇 |
国内免费 | 1040篇 |
专业分类
化学 | 189473篇 |
晶体学 | 6006篇 |
力学 | 19009篇 |
综合类 | 7篇 |
数学 | 44580篇 |
物理学 | 123881篇 |
出版年
2020年 | 3312篇 |
2019年 | 3891篇 |
2018年 | 5418篇 |
2017年 | 5487篇 |
2016年 | 7290篇 |
2015年 | 3907篇 |
2014年 | 6911篇 |
2013年 | 15946篇 |
2012年 | 12062篇 |
2011年 | 14682篇 |
2010年 | 11142篇 |
2009年 | 11262篇 |
2008年 | 13802篇 |
2007年 | 13795篇 |
2006年 | 12735篇 |
2005年 | 11448篇 |
2004年 | 10776篇 |
2003年 | 9613篇 |
2002年 | 9708篇 |
2001年 | 11069篇 |
2000年 | 8403篇 |
1999年 | 6534篇 |
1998年 | 5696篇 |
1997年 | 5456篇 |
1996年 | 5146篇 |
1995年 | 4672篇 |
1994年 | 4632篇 |
1993年 | 4706篇 |
1992年 | 4853篇 |
1991年 | 5279篇 |
1990年 | 4971篇 |
1989年 | 4999篇 |
1988年 | 4883篇 |
1987年 | 4813篇 |
1986年 | 4534篇 |
1985年 | 6008篇 |
1984年 | 6186篇 |
1983年 | 5056篇 |
1982年 | 5385篇 |
1981年 | 5204篇 |
1980年 | 4935篇 |
1979年 | 5270篇 |
1978年 | 5529篇 |
1977年 | 5505篇 |
1976年 | 5657篇 |
1975年 | 5221篇 |
1974年 | 5171篇 |
1973年 | 5349篇 |
1972年 | 4015篇 |
1971年 | 3483篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
121.
Nonlinear Theory of Spectra of Thermally Stimulated Currents in Complex Crystals with Hydrogen Bonds
Tonkonogov M. P. Ismailov Zh. T. Timokhin V. M. Fazylov K. K. Kalitka V. A. Baimukhanov Z. K. 《Russian Physics Journal》2002,45(10):1008-1018
The nonlinear theory of thermally stimulated depolarization currents is developed. The theory explains the processes of hetero- and homocharge relaxation in complex crystals with hydrogen bonds and allows the relaxation oscillator parameters to be calculated using the quadratic approximation for the external electric field. 相似文献
122.
O. Kortner M.P. Locher V.E. Markushin P. Weber O. Wigger 《The European Physical Journal C - Particles and Fields》2002,25(3):353-360
We study correlations in the exclusive reaction at rest with complete reconstruction of the kinematics for each event. The inclusive distribution is fairly flat at small
invariant mass of the pion pair while a small enhancement in the double differential distribution is observed for small invariant
masses of both pion pairs. Dynamical models with resonances in the final state are shown to be consistent with the data while
the stochastic HBT mechanism is not supported by the present findings.
Received: 26 February 2002 / Revised version: 22 July 2002 / Published online: 30 August 2002 相似文献
123.
Z. V. Golubenko A. S. Kamzin L. P. Ol’khovik M. M. Khvorov Z. I. Sizova V. P. Shabatin 《Physics of the Solid State》2002,44(9):1698-1702
Magnetization and remagnetization processes in a close-packed nanodispersed barium hexaferrite powder sample in the magnetically stable state were analyzed. Reversibility effects were discussed in terms of interparticle interaction. Judging from the magnetization curve and the parameters characterizing remagnetization irreversibility, the sample under study is a model system of small Stoner-Wohlfarth particles. 相似文献
124.
D. P. Kouzov 《Journal of Mathematical Sciences》2002,108(5):721-735
A condition for regularization of boundary-contact integrals in two-dimensional problems of acoustics is considered. With an example of the simplest boundary-contact problem of acoustics, it is shown that a known sufficient condition for regularization is also a necessary one. The study of analytic properties of the transition admittance of an infinite plate that is in contact with a medium is conducted in order to obtain this statement. The considerations are carried out in general terms. The results obtained may be used in arbitrary models of plate theory, and they also may be adapted to boundary-contact problems of another physical nature. Bibliography: 9 titles. 相似文献
125.
126.
We discuss a mass change that has its origin in the action of forces on an object. This phenomenon, well-known in the context of quantum field theory (mass renormalization), can be discussed systematically in both classical and quantum mechanics in a framework given by Stückelberg. We employ this framework to resolve an interesting conflict of opinions between Schopenhauer and Hegel in the mid-19th century. We show that Hegel, Kant, and Schopenhauer demonstrated remarkable prescience in their views as seen from a modern perspective. 相似文献
127.
Mutual–temporal coherence of the supercontinuum (SC) generation has been experimentally investigated using a diffraction grating based interferometer. A broadband SC generation was produced in a pyrex glass plate with a 1.6-μm coherence length at 550-nm center wavelength. The degree of mutual coherence of 0.34 was measured for a wavefront shift for zero and first diffraction orders of half of the beam diameter. A design of SC source with the capability of manipulating the amplitudes and phases of optical frequency components within the SC pulse is presented for coherence applications. 相似文献
128.
The conditions for obtaining a high efficiency of energy exchange upon two-wave interactions in dynamic holograms are found by analysis and numerical simulation of a system of nonlinear equations. Use of an asymmetric scheme of beam interaction in a medium with two nonlinearities, one of which determines the amplitude and relaxation time of a grating and the other of which provides phase modulation of the interacting beams, is proposed. It is shown that such a scheme in combination with the specific properties of a medium makes it possible to radically reduce the requirements for the nonlinearity of a medium and the intensity of a light flux in limiting systems, as well as to significantly decrease the time of the transition process. As a result, it becomes possible to attain an efficiency of energy transfer higher than 90% and to increase the corresponding attenuation of a high-power beam by almost two orders of magnitude, which is of interest for optical limiting of intense light fluxes. 相似文献
129.
JETP Letters - The problem of storing ultracold neutrons over a plane magnetic mirror in the presence of gravity is considered. For neutrons with a definite polarization, the sum of the magnetic... 相似文献
130.
I. V. Denisova O. A. Ladyzhenskaya G. A. Seregin N. N. Uraltseva E. V. Frolova 《Journal of Mathematical Sciences》2005,130(4):4775-4779
Bibliography: 42 titles.__________Translated from Zapiski Nauchnykh Seminarov POMI, Vol. 306, 2003, pp. 7–15. 相似文献