全文获取类型
收费全文 | 1181篇 |
免费 | 29篇 |
国内免费 | 2篇 |
专业分类
化学 | 771篇 |
晶体学 | 6篇 |
力学 | 19篇 |
数学 | 211篇 |
物理学 | 205篇 |
出版年
2022年 | 15篇 |
2021年 | 13篇 |
2020年 | 16篇 |
2019年 | 18篇 |
2018年 | 11篇 |
2017年 | 13篇 |
2016年 | 13篇 |
2015年 | 29篇 |
2014年 | 26篇 |
2013年 | 51篇 |
2012年 | 57篇 |
2011年 | 78篇 |
2010年 | 48篇 |
2009年 | 44篇 |
2008年 | 58篇 |
2007年 | 60篇 |
2006年 | 61篇 |
2005年 | 72篇 |
2004年 | 54篇 |
2003年 | 43篇 |
2002年 | 55篇 |
2001年 | 24篇 |
2000年 | 31篇 |
1999年 | 10篇 |
1998年 | 14篇 |
1997年 | 20篇 |
1996年 | 26篇 |
1995年 | 11篇 |
1994年 | 10篇 |
1993年 | 17篇 |
1992年 | 13篇 |
1991年 | 8篇 |
1990年 | 10篇 |
1989年 | 8篇 |
1987年 | 10篇 |
1986年 | 7篇 |
1985年 | 17篇 |
1984年 | 9篇 |
1983年 | 5篇 |
1982年 | 13篇 |
1981年 | 17篇 |
1980年 | 14篇 |
1979年 | 6篇 |
1978年 | 19篇 |
1977年 | 14篇 |
1976年 | 10篇 |
1974年 | 5篇 |
1973年 | 7篇 |
1970年 | 4篇 |
1968年 | 3篇 |
排序方式: 共有1212条查询结果,搜索用时 20 毫秒
81.
The frequency of the v-CO stretching vibration measured by HRELS has been followed as a function of the CO coverage and in the presence of coadsorbed hydrocarbons on the Ni(111) face. The v-CO frequency shifts continuously from 225 meV (1814 cm?1) to 237 meV (1911 cm?1) when the CO coverage increases from 0 to 0.41. Coadsorption of electron donor molecules, such as ethylene and benzene, generates a significant lowering of the v-CO frequency. Results are discussed in terms of the back donation of metallic electrons into the 2π 1 antibonding orbitals of CO, the dipole-dipole coupling and the coordination number of the CO adsorbed molecules. The back donation is found to play the major role in the range of coverage explored but we cannot exclude some contribution of a dipole-dipole coupling effect. 相似文献
82.
83.
84.
85.
86.
We propose to create ultracold ground state molecules in an atomic Bose-Einstein condensate by adiabatic crossing of an optical Feshbach resonance. We envision a scheme where the laser intensity and possibly also frequency are linearly ramped over the resonance. Our calculations for (87)Rb show that for sufficiently tight traps it is possible to avoid spontaneous emission while retaining adiabaticity, and conversion efficiencies of up to 50% can be expected. 相似文献
87.
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
88.
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
89.
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
90.
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