全文获取类型
收费全文 | 2232篇 |
免费 | 22篇 |
专业分类
化学 | 1117篇 |
晶体学 | 9篇 |
力学 | 46篇 |
数学 | 290篇 |
物理学 | 792篇 |
出版年
2018年 | 28篇 |
2017年 | 35篇 |
2016年 | 44篇 |
2015年 | 43篇 |
2014年 | 46篇 |
2013年 | 102篇 |
2012年 | 64篇 |
2011年 | 113篇 |
2010年 | 54篇 |
2009年 | 37篇 |
2008年 | 125篇 |
2007年 | 101篇 |
2006年 | 108篇 |
2005年 | 58篇 |
2004年 | 71篇 |
2003年 | 60篇 |
2002年 | 55篇 |
2001年 | 39篇 |
2000年 | 46篇 |
1999年 | 30篇 |
1998年 | 20篇 |
1997年 | 20篇 |
1995年 | 29篇 |
1994年 | 26篇 |
1993年 | 25篇 |
1992年 | 22篇 |
1989年 | 29篇 |
1988年 | 18篇 |
1987年 | 23篇 |
1986年 | 35篇 |
1985年 | 40篇 |
1984年 | 33篇 |
1983年 | 28篇 |
1982年 | 31篇 |
1981年 | 20篇 |
1980年 | 26篇 |
1979年 | 23篇 |
1978年 | 33篇 |
1977年 | 24篇 |
1976年 | 29篇 |
1975年 | 29篇 |
1974年 | 20篇 |
1972年 | 24篇 |
1969年 | 22篇 |
1968年 | 26篇 |
1967年 | 20篇 |
1966年 | 29篇 |
1963年 | 19篇 |
1961年 | 18篇 |
1960年 | 16篇 |
排序方式: 共有2254条查询结果,搜索用时 15 毫秒
51.
J. Pochylý 《Czechoslovak Journal of Physics》1989,39(10):1089-1110
The problem of the stationary generation by Raman and degenerate hyper-Raman scattering is solved by means of two methods: stationary solution of the generalized Fokker-Planck equation and linear analysis of stability of the Langevin equations. The conditions of stability and the corresponding stationary values for amplitudes of the Stokes, anti-Stokes or output laser modes are obtained for particular cases. A phenomenon analogous to the second order phase transition can occur for Stokes or anti-Stokes interaction of Raman scattering above the threshold value of the pump amplitude. The anti-Stokes interaction of degenerate hyper-Raman scattering can show bistable behaviour above the second threshold value of the pump amplitude.The author would like to express his sincere thanks to Dr. J. Peina for comments and stimulating discussions. 相似文献
52.
The diffusion ot Ti atoms in the Ni77Si3B20 metallic glass was studied by the Auger electron spectroscopy. The temperature dependence of the diffusion coefficient obeys the Arrhenius relation with the activation energyE=1·7 eV and the pre-exponential factorD
0=0·86 × ×10–4 m2 s–1. Possible mechanisms of the atomic transport in metallic glasses are discussedThe authors wish to thank Dr. P. Duhaj for providing the metallic glass samples. 相似文献
53.
Iodice M Cusanno F Acha A Ambrozewicz P Aniol KA Baturin P Bertin PY Benaoum H Blomqvist KI Boeglin WU Breuer H Brindza P Bydzovský P Camsonne A Chang CC Chen JP Choi S Chudakov EA Cisbani E Colilli S Coman L Craver BJ De Cataldo G de Jager CW De Leo R Deur AP Ferdi C Feuerbach RJ Folts E Fratoni R Frullani S Garibaldi F Gayou O Giulani F Gomez J Gricia M Hansen JO Hayes D Higinbotham DW Holmstrom TK Hyde CE Ibrahim HF Jiang X Kaufman LJ Kino K Kross B Lagamba L LeRose JJ Lindgren RA 《Physical review letters》2007,99(5):052501
An experiment measuring electroproduction of hypernuclei has been performed in hall A at Jefferson Lab on a 12C target. In order to increase counting rates and provide unambiguous kaon identification two superconducting septum magnets and a ring imaging Cherenkov detector were added to the hall A standard equipment. An unprecedented energy resolution of less than 700 keV FWHM has been achieved. Thus, the observed (Lambda)(12)B spectrum shows for the first time identifiable strength in the core-excited region between the ground-state s-wave Lambda peak and the 11 MeV p-wave Lambda peak. 相似文献
54.
Sebastian?BreuerEmail author Katrin?Pech Armin?Buss Christoph?Spitzer Juris?Ozols Elly?M?Hol Nicole?Heussen Johannes?Noth Franz-Werner?Schwaiger Andreas?B?Schmitt 《BMC neuroscience》2004,5(1):15
Background
Interruption of mature axons activates a cascade of events in neuronal cell bodies which leads to various outcomes from functional regeneration in the PNS to the failure of any significant regeneration in the CNS. One factor which seems to play an important role in the molecular programs after axotomy is the stearoyl Coenzyme A-desaturase-1 (SCD-1). This enzyme is needed for the conversion of stearate into oleate. Beside its role in membrane synthesis, oleate could act as a neurotrophic factor, involved in signal transduction pathways via activation of protein kinases C. 相似文献55.
Vajda S Lupulescu C Merli A Budzyn F Wöste L Hartmann M Pittner J Bonacić-Koutecký V 《Physical review letters》2002,89(21):213404
We present two-color fs pump-probe spectra of Na2F which were recorded by employing excitation wavelengths around 1208 nm (pump) and ionization wavelengths around 405 nm (probe). The observed oscillatory structure of the signal with a period of 185 fs shows an excellent agreement with our simulated spectra. The employed ab initio Wigner distribution approach provides clear evidence that this observation is caused by photoinduced metal bond breaking followed by a butterfly-type periodic geometric rearrangement. 相似文献
56.
Novák V Olejník K Wunderlich J Cukr M Výborný K Rushforth AW Edmonds KW Campion RP Gallagher BL Sinova J Jungwirth T 《Physical review letters》2008,101(7):077201
We observe a singularity in the temperature derivative drho/dT of resistivity at the Curie point of high-quality (Ga,Mn)As ferromagnetic semiconductors with Tc's ranging from approximately 80 to 185 K. The character of the anomaly is sharply distinct from the critical contribution to transport in conventional dense-moment magnetic semiconductors and is reminiscent of the drho/dT singularity in transition metal ferromagnets. Within the critical region accessible in our experiments, the temperature dependence on the ferromagnetic side can be explained by dominant scattering from uncorrelated spin fluctuations. The singular behavior of drho/dT on the paramagnetic side points to the important role of short-range correlated spin fluctuations. 相似文献
57.
M. Rotter B. Sedlák J. Englich P. Čížek M. Finger P. Malinský 《Czechoslovak Journal of Physics》1986,36(11):1331-1335
The results of NMR/ON measurements on56,57,60Co isotopes in iron are presented in the paper. To avoid the uncertainties caused by local demagnetizing field inhomogeneities the measurements on two cobalt isotopes in one sample have been carried out. The values of nuclear-factors ratios
57/
60=1·805(20),
60/
56 = 0·761(20),
56/
57 = 0·726(20) and hyperfme anomalies56
60 = –0·036(10),60
57 = 0·017(10) and57
56 = 0·018(10) have been calculated from the experimental results.Dedicated to the 30th anniversary of the Joint Institute for Nuclear Research. 相似文献
58.
59.
60.
The motion of a pair of uniform interacting spherical mesoscopic particles situated in a viscous fluid under the influence of a rotating magnetic field was studied. The coupling interactions between the particles were chosen as a superposition of steric and dipolar pair potentials (for the dipoles parallel to the external field). The model dynamics consisting of particular rotation and vibration modes is the result of the interplay of viscous and interaction forces. The transition from the synchronous to the asynchronous regime of dimer rotation has been found. The results were discussed from a synergetic point of view. A qualitative picture of behaviour of the effective magnetoviscosity and permittivity for dimerized magnetorheological suspension has been given. 相似文献