全文获取类型
收费全文 | 586769篇 |
免费 | 7910篇 |
国内免费 | 2457篇 |
专业分类
化学 | 316412篇 |
晶体学 | 8657篇 |
力学 | 25650篇 |
综合类 | 72篇 |
数学 | 70531篇 |
物理学 | 175814篇 |
出版年
2021年 | 4760篇 |
2020年 | 5338篇 |
2019年 | 5788篇 |
2018年 | 7484篇 |
2017年 | 7396篇 |
2016年 | 11205篇 |
2015年 | 7174篇 |
2014年 | 10927篇 |
2013年 | 26457篇 |
2012年 | 20885篇 |
2011年 | 25507篇 |
2010年 | 17955篇 |
2009年 | 17769篇 |
2008年 | 23613篇 |
2007年 | 23583篇 |
2006年 | 21913篇 |
2005年 | 19683篇 |
2004年 | 18045篇 |
2003年 | 15886篇 |
2002年 | 15677篇 |
2001年 | 17570篇 |
2000年 | 13334篇 |
1999年 | 10265篇 |
1998年 | 8622篇 |
1997年 | 8377篇 |
1996年 | 8170篇 |
1995年 | 7268篇 |
1994年 | 7247篇 |
1993年 | 7025篇 |
1992年 | 7769篇 |
1991年 | 7847篇 |
1990年 | 7501篇 |
1989年 | 7261篇 |
1988年 | 7176篇 |
1987年 | 7048篇 |
1986年 | 6764篇 |
1985年 | 8887篇 |
1984年 | 9029篇 |
1983年 | 7330篇 |
1982年 | 7561篇 |
1981年 | 7359篇 |
1980年 | 6809篇 |
1979年 | 7339篇 |
1978年 | 7667篇 |
1977年 | 7593篇 |
1976年 | 7525篇 |
1975年 | 6984篇 |
1974年 | 7064篇 |
1973年 | 7039篇 |
1972年 | 5162篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
871.
872.
873.
Marco Möller 《Results in Mathematics》2004,46(3-4):271-360
874.
An experiment was designed to determine whether normally sighted human subjects would be able to adapt to the handicapping effects of sudden deprivation of visual cues on horizontal plane sound localization. Two groups of sighted normal-hearing young adults participated. One group was allowed the benefit of sight. The other group was blindfolded. Measurements of accuracy and the time to respond were made daily over the course of five consecutive days, in a semi-reverberant sound proof booth that modeled listening in a small office. Sound localization was assessed using an array of eight speakers that surrounded the subject in space. Each day, one block of 120 trials was presented for each of three stimuli, two one-third octave noise bands, centred at 0.5 and 4 kHz, and broadband noise, to assess the utilization of interaural temporal difference cues, interaural level difference cues and binaural and spectral cues in combination. Blindfolded subjects were relatively less accurate than sighted subjects. Both groups showed gains with practice, the blindfolded group to a greater degree, largely due to improvements in the use of spectral cues. The blindfolded group took longer to respond than the sighted group, but showed greater decrements in response time with practice. 相似文献
875.
N. V. Vysotina A. S. Naumov N. N. Rozanov R. L. Sabirov V. E. Semenov V. A. Smirnov T. V. Starchikova S. V. Fedorov S. A. Chizhov V. E. Yashin 《Optics and Spectroscopy》2004,97(3):411-415
The final stage of self-focusing of 500-ps pulses of a neodymium laser in silicate and phosphate glasses and in the nonlinear liquids perfluorooctane, benzene, and toluene is studied theoretically and experimentally. The formation of spatial solitons, which are stable due to the nonlinearity saturation, is demonstrated. It is found that the intensity of the nonlinearity saturation is close to that of the threshold breakdown for glasses and the role of stimulated Raman scattering is significant for liquids. 相似文献
876.
A self-consistent, completely quantum calculation of the structure of the inner crust of neutron stars is carried out in the Wigner-Seitz approximation with a realistic phenomenological nuclear energy functional, where pair correlations of neutrons and protons are included in the explicit form. It has been shown that the superfluidity of neutrons and protons affects the structure of the ground state of the crust. 相似文献
877.
Journal of Statistical Physics - We study high-energy asymptotics of the steady velocity distributions for model kinetic equations describing various regimes in dilute granular flows. The main... 相似文献
878.
The kinetics of formation and relaxation of transient holographic gratings recorded in a system of saturable three-level centers is studied. Distortions in the shape of the profile of recorded and decaying structures of population and of the refractive index are taken into account. The analysis of the time dependences of diffraction efficiencies of different orders is performed for phase (thermal) and amplitude (concentration) gratings. 相似文献
879.
We examine several interesting relationships and expressions involving Fourier-Feynman transform, convolution product and
first variation for functionals in the Fresnel class F(B) of an abstract Wiener space B. We also prove a translation theorem and Parseval's identity for the analytic Feynman integral.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
880.
Jacob Schach Møller 《Annales Henri Poincare》2005,6(6):1091-1135
In this paper we analyze the bottom of the energy-momentum spectrum of the translation invariant Nelson model, describing
one electron linearly coupled to a second quantized massive scalar field. Our results are valid for all values of the coupling
constant and include an HVZ theorem, non-degeneracy of ground states, existence of isolated groundstates in dimensions 1 and
2, non-existence of ground states embedded in the bottom of the essential spectrum in dimensions 3 and 4, (i.e., at total
momenta where no isolated groundstate eigenvalue exists), and we study regularity and monotonicity properties of the bottom
of the essential spectrum, as a function of total momentum.
Communicated by Joel Feldman
submitted 04/11/04, accepted 17/02/05 相似文献