全文获取类型
收费全文 | 342533篇 |
免费 | 3015篇 |
国内免费 | 346篇 |
专业分类
化学 | 164023篇 |
晶体学 | 4943篇 |
力学 | 17595篇 |
综合类 | 4篇 |
数学 | 50971篇 |
物理学 | 108358篇 |
出版年
2021年 | 3544篇 |
2020年 | 4062篇 |
2019年 | 4826篇 |
2018年 | 7165篇 |
2017年 | 7292篇 |
2016年 | 9516篇 |
2015年 | 4897篇 |
2014年 | 8224篇 |
2013年 | 15066篇 |
2012年 | 12845篇 |
2011年 | 14374篇 |
2010年 | 11752篇 |
2009年 | 11646篇 |
2008年 | 13673篇 |
2007年 | 13229篇 |
2006年 | 11834篇 |
2005年 | 10468篇 |
2004年 | 9975篇 |
2003年 | 9098篇 |
2002年 | 9207篇 |
2001年 | 8543篇 |
2000年 | 6928篇 |
1999年 | 5103篇 |
1998年 | 4771篇 |
1997年 | 4536篇 |
1996年 | 4319篇 |
1995年 | 3715篇 |
1994年 | 3842篇 |
1993年 | 3816篇 |
1992年 | 3839篇 |
1991年 | 4167篇 |
1990年 | 4203篇 |
1989年 | 4129篇 |
1988年 | 3867篇 |
1987年 | 3932篇 |
1986年 | 3624篇 |
1985年 | 4264篇 |
1984年 | 4476篇 |
1983年 | 3803篇 |
1982年 | 3999篇 |
1981年 | 3685篇 |
1980年 | 3398篇 |
1979年 | 3862篇 |
1978年 | 3949篇 |
1977年 | 4123篇 |
1976年 | 4179篇 |
1975年 | 3881篇 |
1974年 | 3753篇 |
1973年 | 3924篇 |
1972年 | 3320篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
V. G. Osmolovski 《Journal of Mathematical Sciences》1997,84(1):898-910
An existence theorem for the variational problem for the two-phase medium energy functional is proved. Dependence of the solution
on the surface tension coefficient and on the temperature is investigated. Bibliography: 7 titles.
Dedicated to V. A. Solonnikov on his sixtieth anniversary
Translated fromZapiski Nauchnykh Seminarov POMI, Vol. 213, 1994, pp. 131–150.
Translated by S. Yu. Pilyugin. 相似文献
992.
An iterative method from the class of completely implicit methods (CIM) is proposed for solving the equation of the velocity
potential of elliptical-hyperbolic type. The advantage of the proposed method compared to other CIM schemes is demonstrated
in application to mixed perfect gas flows in a nozzle of a given shape. Accuracy issues, rate of convergence, and various
techniques of ensuring stability in the hyperbolic region are discussed.
Translated from Chislennye Metody v Matematicheskoi Fizike, Published by Moscow University, Moscow, 1996, pp. 39–51. 相似文献
993.
994.
D. V. Peregoudov 《Theoretical and Mathematical Physics》1997,113(1):1331-1341
The effective potential method, used in quantum field theory to study spontaneous symmetry violation, is discussed from the
point of view of Bogoliubov’s quasi-averaging procedure. It is shown that the effective potential method is a disguised type
of this procedure. The catastrophe theory approach to the study of phase transitions is discussed and the existence of the
potentials used in that approach is proved from the statistical point of view. It is shown that in the case of broken symmetry,
the nonconvex effective potential is not a Legendre transform of the generating functional for connected Green’s functions.
Instead, it is a part of the potential used in catastrophe theory. The relationship between the effective potential and the
Legendre transform of the generating functional for connected Green’s functions is given by Maxwell’s rule. A rigorous rule
for evaluating quasi-averaged quantities within the framework of the effective potential method is established.
Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 113, No. 1, pp. 149–161, October, 1997. 相似文献
995.
996.
V. A. Zubkov S. N. Kovalenko V. P. Chernykh S. M. Ivkov 《Chemistry of Heterocyclic Compounds》1994,30(6):665-670
Methods of synthesizing previously unknown derivatives of coumarin — 2-(N-R-imino)-2H-1-benzopyrans, where R = Alk, Ar — are proposed. Possibilities of alternative synthetic schemes are discussed, and hypotheses concerning probable mechanisms of the reactions are formulated.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 760–766, June, 1994. Original article submitted May 23, 1994. 相似文献
997.
V. P. Kondilenko V. Ya. Chorny A. M. Eremenko 《Reaction Kinetics and Catalysis Letters》1993,50(1-2):203-207
The influence of temperature in the 20–100°C range on processes of bimolecular interaction in the aerosil-phenanthrene-trinitrobenzene system has been studied. Temperature-stimulated CTC accumulation on the surface is found. Activation energies of complex formation are estimated. Quenching of phenanthrene fluorescence by acceptor has a mixed static and dynamic character. 相似文献
998.
V. M. Ogenko A. V. Fesenko N. D. Konovalova V. I. Stepanenko 《Reaction Kinetics and Catalysis Letters》1993,50(1-2):169-173
It has been established that CO oxidation with excess O2 on Ni/Al2O3 forms an inhomogeneous NiO contact surface that smoothes critical effects in the sharp reactivity change. 相似文献
999.
Ricardo García-Pelayo Iván Salazar William C. Schieve 《Journal of statistical physics》1993,72(1-2):167-187
An analytically solvable model for sand avalanches of noninteracting grains of sand, based on the Chapman-Kolmogorov equations, is presented. For a single avalanche, distributions of lifetimes, sizes of overflows and avalanches, and correlation functions are calculated. Some of these are exponentials, some are power laws. Spatially homogeneous distributions of avalanches are also studied. Computer simulations of avalanches of interacting grains of sand are compared to the solutions to the Chapman-Kolmogorov equations. We find that within the range of parameters explored in the simulation, the approximation of noninteracting grains of sand is a good one. 相似文献
1000.
X-ray photoelectron and Auger spectroscopies were used to examine surface bonding and overlayer growth during palladium and copper deposition onto films of fullerene, C60 The results were consistent with metal cluster formation on C60. The observed positive core electron binding energy shifts in small metallic clusters supported on C60 were shown to originate in metal-fullerene interaction accompanied by charge transfer. Palladium-fullerene intermixing at temperatures as low as ss 50°C was observed for small Pd coverages. 相似文献