全文获取类型
收费全文 | 364215篇 |
免费 | 1362篇 |
国内免费 | 349篇 |
专业分类
化学 | 156444篇 |
晶体学 | 5380篇 |
力学 | 22483篇 |
综合类 | 3篇 |
数学 | 61516篇 |
物理学 | 120100篇 |
出版年
2021年 | 3095篇 |
2020年 | 3412篇 |
2019年 | 4191篇 |
2018年 | 11864篇 |
2017年 | 12350篇 |
2016年 | 10666篇 |
2015年 | 3968篇 |
2014年 | 6932篇 |
2013年 | 12166篇 |
2012年 | 13163篇 |
2011年 | 20442篇 |
2010年 | 14693篇 |
2009年 | 15024篇 |
2008年 | 18741篇 |
2007年 | 21158篇 |
2006年 | 10086篇 |
2005年 | 12392篇 |
2004年 | 10251篇 |
2003年 | 10149篇 |
2002年 | 9151篇 |
2001年 | 7768篇 |
2000年 | 6339篇 |
1999年 | 4523篇 |
1998年 | 4290篇 |
1997年 | 4135篇 |
1996年 | 3904篇 |
1995年 | 3403篇 |
1994年 | 3452篇 |
1993年 | 3455篇 |
1992年 | 3449篇 |
1991年 | 3863篇 |
1990年 | 3865篇 |
1989年 | 3881篇 |
1988年 | 3640篇 |
1987年 | 3719篇 |
1986年 | 3404篇 |
1985年 | 3944篇 |
1984年 | 4195篇 |
1983年 | 3588篇 |
1982年 | 3782篇 |
1981年 | 3468篇 |
1980年 | 3225篇 |
1979年 | 3733篇 |
1978年 | 3807篇 |
1977年 | 3889篇 |
1976年 | 3999篇 |
1975年 | 3725篇 |
1974年 | 3578篇 |
1973年 | 3780篇 |
1972年 | 3217篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
131.
132.
133.
D. Yu. Gladilov S. Yu. Nekhaevskii A. V. Ochkin 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2006,80(12):1934-1939
Various methods for describing the distribution of water in the H2O-tributyl phosphate (TBP) system were considered. An equation for describing the deviations from the Henry law was proposed. A three-parameter equation for calculating the distribution of water in H2O-TBP-solvent systems was derived. It is based on the additive solubility model and allows for the dependence of the activity coefficients on the TBP concentration. Based on the published data, the parameters of the equation for a number of systems were calculated. 相似文献
134.
A. A. Abramov S. V. Kurochkin 《Computational Mathematics and Mathematical Physics》2006,46(6):949-954
A new method for calculating the radial spheroidal functions of the first kind is proposed for the arguments that are greater than unity in modulus. A well-known representation of these functions is refined and used for this purpose. The constructs and the software implementation proposed in the paper provide an efficient tool for the calculation of the functions with a desired accuracy in a wide range of parameters. 相似文献
135.
Evstafyeva I. T. Bozhenkov G. V. Aizina Ya. A. Rozenzveig I. B. Ermakova T. G. Levkovskaya G. G. Mirskova A. N. 《Russian Journal of Organic Chemistry》2002,38(8):1178-1182
1H-Pyrazoles, triazoles, and imidazoles in reaction with ethoxycarbonylimine and arylsulfonylimines of chloral yield addition products, corresponding 1-(1-amidotrichloroethyl)azoles. Derivatives of 1-alkylpyrazoles and pyrazolones react with chloral 4-chlorophenylsulfonylimine to furnish products of C-amidotrichloroethylation into position 4 of the azole ring. 相似文献
136.
V. I. Korobov 《Few-Body Systems》2002,31(2-4):133-138
In this contribution we consider a phenomenon of metastable states in antiprotonic helium atoms, precise spectroscopy of
these states and a present-day study of the electromagnetic properties of antiprotons.
Received October 16, 2001; accepted for publication November 13, 2001 相似文献
137.
The effect of hydrogen on the photoluminescence and planar conductivity of GaAs/InGaAs quantum-well heterostructures with an island Pd layer at the anodically oxidized surface was studied. Unlike continuous deposited Pd layers, island layers do not cause the formation of defects in the GaAs surface region and yet the Pd layer maintains high catalytic activity with respect to hydrogen. It is found that the thermal treatment of such a structure in a hydrogen atmosphere causes atomic-hydrogen passivation of the defects in quantum wells. Studies of the characteristics of planar photoresistors with an island Pd layer acting as hydrogen sensors show that their hydrogen detectivity is approximately two orders of magnitude higher than that of diode structures with continuous Pd layers. 相似文献
138.
E. V. Gromachevskaya A. G. Sakhabutdinov V. G. Kul'nevich I. S. Arustamova R. B. Valeev B. A. Bazhenov 《Chemistry of Heterocyclic Compounds》1991,27(5):502-503
It was shown that the reaction of o-hyroxyphenyldiphenylmethanol with benzaldehyde labeled with 17O and 18O isotopes proceeds in such a way that oxygen atoms of the starting phenoloalcohol are retained.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 632–633, May, 1991. 相似文献
139.
V. Čápek 《Czechoslovak Journal of Physics》1991,41(10):975-989
A review of ideas leading to full rejection of any finite or partially-infinite order kinetic equation linearized in external field is given on grounds of the time-convolution Generalized Master Equations (GME). By two examples (two-level and band conduction problem), it is shown how standard kinetic equations result from GME in the lowest order approximations which obscure, however, a direct correspondence with the Kubo linear response theory. Without approximations, on the other hand, the rigorous approach is shown to be fully equivalent with the Kubo results. It is argued and illustrated that usual technical simplicity and seeming physical lucidity of standard theories (connected with the presence of field-independent transfer or scattering rates in the fielddependent linearized theory) are just owing to structural features which are solely due to the lowest order approximations involved. These features (i.e. also the possibility of standard physical interpretation of kinetic phenomena) are proved to disappear completely as far as the theory goes properly to higher orders. 相似文献
140.