全文获取类型
收费全文 | 91951篇 |
免费 | 16242篇 |
国内免费 | 75篇 |
专业分类
化学 | 83156篇 |
晶体学 | 284篇 |
力学 | 3593篇 |
数学 | 10130篇 |
物理学 | 11105篇 |
出版年
2024年 | 398篇 |
2023年 | 4268篇 |
2022年 | 1631篇 |
2021年 | 2811篇 |
2020年 | 4988篇 |
2019年 | 2768篇 |
2018年 | 3163篇 |
2017年 | 1389篇 |
2016年 | 6729篇 |
2015年 | 6486篇 |
2014年 | 5968篇 |
2013年 | 7665篇 |
2012年 | 6353篇 |
2011年 | 4406篇 |
2010年 | 5221篇 |
2009年 | 4755篇 |
2008年 | 3932篇 |
2007年 | 3698篇 |
2006年 | 2717篇 |
2005年 | 2622篇 |
2004年 | 2246篇 |
2003年 | 1829篇 |
2002年 | 1580篇 |
2001年 | 951篇 |
2000年 | 789篇 |
1999年 | 571篇 |
1998年 | 435篇 |
1997年 | 453篇 |
1996年 | 542篇 |
1995年 | 432篇 |
1994年 | 442篇 |
1993年 | 558篇 |
1992年 | 475篇 |
1985年 | 477篇 |
1984年 | 452篇 |
1982年 | 454篇 |
1981年 | 467篇 |
1980年 | 468篇 |
1979年 | 451篇 |
1978年 | 437篇 |
1977年 | 513篇 |
1976年 | 622篇 |
1975年 | 690篇 |
1974年 | 716篇 |
1973年 | 518篇 |
1972年 | 469篇 |
1971年 | 432篇 |
1970年 | 611篇 |
1969年 | 488篇 |
1968年 | 522篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
63.
We prove global existence of solutions to the continuous nonhomogeneous Smoluchowski equation for coagulation rates satisfying a more general structure condition than the Galkin–Tupchiev monotony hypothesis considered in (Ph. Laurençot, S. Mischler, Arch. Rational Mech. Anal. 162 (1) (2002) 45–99). The Smoluchowski coagulation rate fulfils this condition as well as some rates which vanish on the diagonal. Under the condition of positivity of the coagulation rate outside of the diagonal we prove that solutions tend to 0 in the large time asymptotic. These results depend on a new estimate from below for the dissipation rate of the Lp-norm, p>1. To cite this article: S. Mischler, M. Rodriguez Ricard, C. R. Acad. Sci. Paris, Ser. I 336 (2003). 相似文献
64.
M. Dubé C. Daneault V. Vuorinen M. Alava M. Rost 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,56(1):15-26
We investigate the structure and dynamics of the interface between
two immiscible liquids in a three-dimensional disordered porous
medium. We apply a phase-field model that includes explicitly
disorder and discuss both spontaneous and forced imbibition.
The structure of the interface is dominated by a length scale
ξ× which arises from liquid conservation. We further show
that disorder in the capillary and permeability act on different
length scales and give rise to different scalings and
structures of the interface properties. We conclude with a
range of applications. 相似文献
65.
G. Bouwmans B. Ségard P. Glorieux P. A. Khandokhin N. D. Milovsky E. Yu. Shirokov 《Radiophysics and Quantum Electronics》2004,47(10-11):729-742
This paper is devoted to the polarization dynamics of a longitudinally monomode bipolarized Nd:YAG laser: the low-frequency polarization dynamics of a microchip laser is studied experimentally and theoretically. The intensities and the relaxation oscillation spectrum of orthogonally polarized modes versus the direction of pump polarization is observed. A phase-sensitive model of a longitudinally monomode bipolarized solid-state laser with linear polarized diode laser pump is developed to account for the experimental observations. 相似文献
66.
A palladium‐TPPTS catalyst heterogenized on KF/alumina has been shown to be effective and recyclable for the selective formation of monooctadienylxylopyranosides via the telomerization of butadiene with D ‐xylose. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
67.
A. Veiga N. Martínez P. Mendoza Zélis G. A. Pasquevich F. H. Sánchez 《Hyperfine Interactions》2006,167(1-3):905-909
A prototype of a programmable constant-velocity scaler is presented. This instrument allows the acquisition of partial Mössbauer spectra in selected energy regions using standard drivers and transducers. It can be fully operated by a remote application, thus data acquisition can be automated. The instrument consists of a programmable counter and a constant-velocity reference. The reference waveform generator is amplitude modulated with 13-bit resolution, and is programmable in a wide range of frequencies and waveforms in order to optimize the performance of the transducer. The counter is compatible with most standard SCA, and is configured as a rate-meter that provides counts per selectable time slice at the programmed velocity. As a demonstration of the instrument applications, a partial Mössbauer spectrum of a natural iron foil was taken. Only positive energies were studied in 512 channels, accumulating 20 s per channel. A line width of 0.20 mm/s was achieved, performing with an efficiency of 80%. 相似文献
68.
The aim of this article is to give a new dynamical proof of the Ferrand–Obata theorem when the manifold is compact. This will give us a generalisation of this theorem to transversally conformal foliations ofcodimension greater than three and constant basic functions. 相似文献
69.
70.