全文获取类型
收费全文 | 498044篇 |
免费 | 6338篇 |
国内免费 | 1460篇 |
专业分类
化学 | 235918篇 |
晶体学 | 6516篇 |
力学 | 18875篇 |
综合类 | 13篇 |
数学 | 50322篇 |
物理学 | 133892篇 |
无线电 | 60306篇 |
出版年
2021年 | 4315篇 |
2020年 | 4818篇 |
2019年 | 5150篇 |
2018年 | 6559篇 |
2017年 | 6345篇 |
2016年 | 9722篇 |
2015年 | 6001篇 |
2014年 | 9482篇 |
2013年 | 21819篇 |
2012年 | 16707篇 |
2011年 | 20498篇 |
2010年 | 14783篇 |
2009年 | 15338篇 |
2008年 | 20111篇 |
2007年 | 20437篇 |
2006年 | 19093篇 |
2005年 | 17337篇 |
2004年 | 16153篇 |
2003年 | 14430篇 |
2002年 | 14087篇 |
2001年 | 15794篇 |
2000年 | 12409篇 |
1999年 | 10052篇 |
1998年 | 8621篇 |
1997年 | 8290篇 |
1996年 | 7980篇 |
1995年 | 7219篇 |
1994年 | 7120篇 |
1993年 | 6755篇 |
1992年 | 7389篇 |
1991年 | 7481篇 |
1990年 | 7126篇 |
1989年 | 6796篇 |
1988年 | 6626篇 |
1987年 | 6010篇 |
1986年 | 5651篇 |
1985年 | 7202篇 |
1984年 | 7278篇 |
1983年 | 5823篇 |
1982年 | 5825篇 |
1981年 | 5807篇 |
1980年 | 5368篇 |
1979年 | 5668篇 |
1978年 | 5791篇 |
1977年 | 5691篇 |
1976年 | 5577篇 |
1975年 | 5145篇 |
1974年 | 5111篇 |
1973年 | 5126篇 |
1972年 | 3626篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
O. Perru F. Ibrahim O. Bajeat C. Bourgeois F. Clapier E. Cottereau C. Donzaud M. Ducourtieux S. Galès D. Guillemaud-Mueller C. Lau H. Lefort F. Le Blanc A. C. Mueller J. Obert N. Pauwels J. C. Potier F. Pougheon J. Proust B. Roussière J. Sauvage O. Sorlin D. Verney 《Physics of Atomic Nuclei》2003,66(8):1421-1427
The PARRNe facility has been used to produce neutron-rich isotopes 83,84Gaby the ISOL method. Their decay has been studied, and β-γ coincidence and γ-γ coincidence data were collected as a function of time. The first two excited levels in 83Ge and the first excited level in 84Ge have been measured for the first time. 相似文献
993.
The problem of finding the Euclidean distance between two convex polyhedra can be reduced to the combinatorial optimization problem of finding the minimum distance between their faces. This paper presents a global optimality criterion for this problem. An algorithm (QLDPA) for the fast computation of the distance between convex and bounded polyhedra is proposed as an application of it. Computer experiments show its fast performance, especially when the total number of vertices is large. 相似文献
994.
995.
Marco Möller 《Results in Mathematics》2004,46(3-4):271-360
996.
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
997.
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
998.
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
999.
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
1000.
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