全文获取类型
收费全文 | 589438篇 |
免费 | 26981篇 |
国内免费 | 18172篇 |
专业分类
化学 | 292049篇 |
晶体学 | 8897篇 |
力学 | 33416篇 |
综合类 | 30篇 |
数学 | 82534篇 |
物理学 | 217665篇 |
出版年
2021年 | 5623篇 |
2020年 | 6190篇 |
2019年 | 7638篇 |
2018年 | 10323篇 |
2017年 | 11255篇 |
2016年 | 14369篇 |
2015年 | 8713篇 |
2014年 | 13532篇 |
2013年 | 27867篇 |
2012年 | 22850篇 |
2011年 | 27333篇 |
2010年 | 23326篇 |
2009年 | 23950篇 |
2008年 | 23913篇 |
2007年 | 23122篇 |
2006年 | 21195篇 |
2005年 | 19003篇 |
2004年 | 19021篇 |
2003年 | 16763篇 |
2002年 | 16764篇 |
2001年 | 18127篇 |
2000年 | 13889篇 |
1999年 | 11296篇 |
1998年 | 9845篇 |
1997年 | 9387篇 |
1996年 | 9104篇 |
1995年 | 8498篇 |
1994年 | 8653篇 |
1993年 | 8587篇 |
1992年 | 8478篇 |
1991年 | 8681篇 |
1990年 | 8135篇 |
1989年 | 8086篇 |
1988年 | 7695篇 |
1987年 | 7308篇 |
1986年 | 6905篇 |
1985年 | 7991篇 |
1984年 | 8315篇 |
1983年 | 6731篇 |
1982年 | 7223篇 |
1981年 | 6728篇 |
1980年 | 6502篇 |
1979年 | 6923篇 |
1978年 | 6989篇 |
1977年 | 7100篇 |
1976年 | 7387篇 |
1975年 | 6476篇 |
1974年 | 6289篇 |
1973年 | 6567篇 |
1972年 | 5253篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
111.
E. V. Morozov 《Journal of Mathematical Sciences》1991,57(4):3302-3305
Translated fromProblemy Ustoichivosti Stokhasticheskikh Modelei. Trudy Seminara, 1988, pp. 115–120. 相似文献
112.
A. V. Ponosov 《Journal of Mathematical Sciences》1991,56(3):2492-2496
We study properties of some linear and nonlinear operators which occur in the theory of stochastic differential and integral equations.Translated from Statisticheskie Metody Otsenivaniya i Proverki Gipotez, pp. 148–154, 1988. 相似文献
113.
A. I. Bril' V. P. Kabashnikov N. V. Kuz'mina Yu. V. Khodyko 《Journal of Applied Spectroscopy》1991,55(3):934-939
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 55, No. 3, pp. 478–484, September, 1991. 相似文献
114.
V. K. Malyutenko A. I. Liptuga V. A. Botte V. I. Chernyakhovskii 《Journal of Applied Spectroscopy》1991,55(4):1024-1028
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 55, No. 4, pp. 624–629, October, 1991. 相似文献
115.
The stressed state of a thick three-layer plate with two circular holes is studied. Resolving functions are expressed in terms of Kolosov-Muskhelishvili integral potentials and modified Bessel functions. The problem is reduced to solving an infinite set of linear algebraic equations.Translated from Teoreticheskaya i Prikladnaya Mekhanika, No. 18, pp. 25–28, 1987. 相似文献
116.
A three-dimensional quasiclassical trajectory study of the dynamics of the light atom transfer reaction O(3P) + HCl(ν=0)→ OH + Cl was carried out employing two LEPS potential energy surfaces (I and II). Attention was focused mainly on three-dynamical properties; the oscillatory behavior of partial cross sections as a function of collision energy; the rotational excitation of the products; and the influence of reagent rotation on reactivity. Distinct differences were found between surfaces I and II with respect to these properties. The examination of individual trajectories indicated that there is a significant difference in the nature of these surfaces. While surface I is governed by weak repulsive forces, surface II is governed by strong attractive forces which tend to direct the reactants toward a collinear geometry. The present results confirm conclusions reached from an earlier study of the reaction Cl+HCl→ClH+Cl concerning correlations between dynamical properties and features of potential energy surfaces. For surfaces of the type that we termed HREP, since they are of repulsive nature and they lead to highly rotationally excited products, no significant oscillations of partial cross sections are obtained and reagent rotation promotes the reaction. On the other hand, for surfaces of the type that we termed COLD (collinearly directing), since they tend to direct the reactants toward a collinear geometry and form rotationally “cold” products, significant oscillations of partial cross sections are obtained and reagent rotation causes a decline in reactivity. 相似文献
117.
V. V. Tokarchuk 《Journal of Applied Mathematics and Mechanics》1989,53(6):708-715
The Langevin dynamics and fluctuational-dissipative relationships for the hydrodynamic fluctuations for systems which are described in the third Barnett order with respect to the gradients of the hydrodynamic variables are generalized on the basis of a kinetic approach. 相似文献
118.
119.
120.
This paper examines the non-linear dynamic behaviour of a flexible shaft. The shaft is mounted on two journal bearings and the axial load is supported by a defective hydrodynamic thrust bearing at one end. The defect is a levelness defect of the rotor. The thrust bearing behaviour must be considered to be non-linear because of the effects of the defect. The shaft is modelled with typical beam finite elements including effects such as the gyroscopic effects. A modal technique is used to reduce the number of degrees of freedom. Results show that the thrust bearing defects introduce supplementary critical speeds. The linear approach is unable to show the supplementary critical speeds which are obtained only by using non-linear analysis. 相似文献