全文获取类型
收费全文 | 747篇 |
免费 | 22篇 |
国内免费 | 1篇 |
专业分类
化学 | 432篇 |
力学 | 16篇 |
数学 | 146篇 |
物理学 | 176篇 |
出版年
2022年 | 4篇 |
2021年 | 10篇 |
2020年 | 9篇 |
2019年 | 11篇 |
2018年 | 8篇 |
2017年 | 4篇 |
2016年 | 10篇 |
2015年 | 17篇 |
2014年 | 20篇 |
2013年 | 27篇 |
2012年 | 43篇 |
2011年 | 65篇 |
2010年 | 33篇 |
2009年 | 25篇 |
2008年 | 38篇 |
2007年 | 36篇 |
2006年 | 48篇 |
2005年 | 46篇 |
2004年 | 38篇 |
2003年 | 31篇 |
2002年 | 29篇 |
2001年 | 17篇 |
2000年 | 20篇 |
1999年 | 6篇 |
1998年 | 6篇 |
1997年 | 12篇 |
1996年 | 8篇 |
1995年 | 8篇 |
1994年 | 8篇 |
1993年 | 9篇 |
1992年 | 8篇 |
1991年 | 6篇 |
1990年 | 4篇 |
1989年 | 3篇 |
1987年 | 5篇 |
1985年 | 10篇 |
1984年 | 8篇 |
1982年 | 6篇 |
1981年 | 8篇 |
1980年 | 6篇 |
1979年 | 6篇 |
1978年 | 14篇 |
1977年 | 8篇 |
1976年 | 4篇 |
1975年 | 3篇 |
1974年 | 5篇 |
1973年 | 3篇 |
1972年 | 3篇 |
1970年 | 3篇 |
1968年 | 3篇 |
排序方式: 共有770条查询结果,搜索用时 375 毫秒
61.
62.
Cédric Rousseau 《Bulletin of the Brazilian Mathematical Society》2005,36(3):379-391
Let A be a symmetric hyperbolic matrix in SL(2, ℤ) and Γ the subgroup of SL(2, ℤ) generated by A. We aim to study the infinitesimal rigidity of the standard action of Γ on the torus
. More precisely, we will consider the Sobolev Ws–infinitesimal rigidity of this action (that is to determine if the cohomology space H1(Γ,Ws (T M)) is trivial or not), and show that it is Ws–infinitesimally rigid only if 0 ≤ s < 1. A consequence will be that this action is not C∞–infinitesimally rigid.
*I would like to thank A. El Kacimi for introducing me this problem about which we had many fruitful discussions. 相似文献
63.
Glinec Y Faure J Dain LL Darbon S Hosokai T Santos JJ Lefebvre E Rousseau JP Burgy F Mercier B Malka V 《Physical review letters》2005,94(2):025003
An electron beam from a laser-plasma accelerator is converted into a gamma-ray source using bremsstrahlung radiation in a dense material. The gamma-ray beam has a pointlike source size because it is generated by a high quality electron beam with a small source size and a low divergence. Using this gamma-ray source, the radiography of complex and dense objects with submillimeter resolution is performed. It is the first evidence of a gamma-ray source size of a few hundreds micrometers produced with laser-driven accelerators. This size is consistent with results from Monte Carlo simulations. 相似文献
64.
We show that soft-core bosons in two dimensions with a ring exchange term exhibit a tendency for phase separation. This observation suggests that the thermodynamic stability of normal Bose liquid phases driven by ring exchange should be carefully examined. 相似文献
65.
Schreiner E Nicolini C Ludolph B Ravindra R Otte N Kohlmeyer A Rousseau R Winter R Marx D 《Physical review letters》2004,92(14):148101
The temperature-dependent behavior of a solvated oligopeptide, GVG(VPGVG), is investigated. Spectroscopic measurements, thermodynamic measurements, and molecular dynamics simulations find that this elastinlike octapeptide behaves as a two-state system that undergoes an "inverse temperature" folding transition and reentrant unfolding close to the boiling point of water. A molecular picture of these processes is presented, emphasizing changes in the dynamics of hydrogen bonding at the protein/water interface and peptide backbone librational entropy. 相似文献
66.
67.
S. Torilov S. Thummerer W. von Oertzen Tz Kokalova G. de Angelis H. G. Bohlen A. Tumino M. Axiotis E. Farnea N. Marginean T. Martinez D. R. Napoli M. De Poli S. M. Lenzi C. Ur M. Rousseau P. Papka 《The European Physical Journal A - Hadrons and Nuclei》2004,19(3):307-317
We have studied the reactions
as well as the binary channel
, in order to search for deformed states, which form rotational bands in 40Ca. We observe positive- and negative-parity bands. The negative-parity band is proposed to be a partner of an inversion doublet with the positive-parity states being based on 4p-4h configurations. The properties of the positive-parity states are discussed on the basis of the shell model and the parity doublet on the basis of a cluster model with intrinsic reflection asymmetric shapes.Received: 2 May 2003, Revised: 23 September 2003, Published online: 20 January 2004PACS:
21.10.-k Properties of nuclei; nuclear energy levels - 21.60.Gx Cluster models 相似文献
68.
Konôpka M Rousseau R Stich I Marx D 《Journal of the American Chemical Society》2004,126(38):12103-12111
The interaction of alkanethiolates with small coinage metal clusters of copper and gold was studied based on density functional theory with a focus on the metal-thiolate junction. Calculation of fragmentation energies indicate that for Cu(n)-thiolate (n = 1,3,5,7, and 9) there is a progressive lowering in energy for the fragmentation of the S-C bond in the thiolate from a value of 2.9 eV for n = 1 to 1.4 eV for n = 9. The detailed electronic origins of this specific weakening are attributed to a polarization of electron density in the S-C bond as induced by bonding with the Cu(n) cluster. For the gold analogues, this effect is not observed and fragmentation at the S-C bond experiences only a slight 10% destabilization as n increases from 3 to 9. The relativistic origin of this difference between Cu and Au is discussed, and an analysis of bonding considerations is presented. 相似文献
69.
In this paper, te edge mode variation is studied with three different methods: the reciprocal work method, already used by Torvik [J. Acoust. Soc. Am. 41 (1967) 346] to model this phenomenon, the S-parameter method and a finite element model that are applied for the first time to the study of the edge resonance. Moreover, laser probe measurements of the edge mode have also been performed and compared to the numerical predictions. The good agreement between the numerical predictions and the experimental data allows full understanding of the resonant phenomenon. The edge resonance is linked to the strong increase in amplitude of two complex Lamb waves, and the edge mode is proved to radiate into the plate as the first symmetrical Lamb mode S(0). Displacements at the edge and away from the edge have been computed and measured to evaluate the spatial and temporal behaviour of the edge mode. The dependence of the edge resonance frequency and amplitude on the Poisson coefficient has also been studied. 相似文献
70.
A water-soluble and "self-assembled" polyoxometalate as a recyclable catalyst for oxidation of alcohols in water with hydrogen peroxide 总被引:1,自引:0,他引:1
Sloboda-Rozner D Alsters PL Neumann R 《Journal of the American Chemical Society》2003,125(18):5280-5281
We have demonstrated that a simply prepared water-soluble polyoxometalate, Na12[WZnZn2(H2O)2(ZnW9O34)2], synthesized from readily available zinc and tungsten salts in the presence of nitric acid, is an effective catalyst for selective alcohol oxidation with hydrogen peroxide in biphasic (water-alcohol) reaction media. Experiments have shown that the "self-assembled" catalyst in its mother liquor was as active as the isolated catalyst. The aqueous catalyst solution is easily separated from the water-insoluble products and can be recycled without loss in activity or selectivity. 相似文献