全文获取类型
收费全文 | 585998篇 |
免费 | 4624篇 |
国内免费 | 1208篇 |
专业分类
化学 | 270196篇 |
晶体学 | 8803篇 |
力学 | 33212篇 |
综合类 | 10篇 |
数学 | 89880篇 |
物理学 | 189729篇 |
出版年
2021年 | 5056篇 |
2020年 | 5400篇 |
2019年 | 6315篇 |
2018年 | 13238篇 |
2017年 | 13647篇 |
2016年 | 14407篇 |
2015年 | 6795篇 |
2014年 | 11490篇 |
2013年 | 24095篇 |
2012年 | 21381篇 |
2011年 | 29169篇 |
2010年 | 21188篇 |
2009年 | 21571篇 |
2008年 | 26589篇 |
2007年 | 28278篇 |
2006年 | 19054篇 |
2005年 | 19314篇 |
2004年 | 17013篇 |
2003年 | 15925篇 |
2002年 | 15061篇 |
2001年 | 15709篇 |
2000年 | 12157篇 |
1999年 | 9171篇 |
1998年 | 8059篇 |
1997年 | 7731篇 |
1996年 | 7303篇 |
1995年 | 6411篇 |
1994年 | 6377篇 |
1993年 | 6249篇 |
1992年 | 6577篇 |
1991年 | 7113篇 |
1990年 | 6830篇 |
1989年 | 6770篇 |
1988年 | 6401篇 |
1987年 | 6576篇 |
1986年 | 6145篇 |
1985年 | 7473篇 |
1984年 | 7766篇 |
1983年 | 6557篇 |
1982年 | 6718篇 |
1981年 | 6295篇 |
1980年 | 6085篇 |
1979年 | 6723篇 |
1978年 | 6773篇 |
1977年 | 6831篇 |
1976年 | 6879篇 |
1975年 | 6430篇 |
1974年 | 6245篇 |
1973年 | 6454篇 |
1972年 | 5023篇 |
排序方式: 共有10000条查询结果,搜索用时 515 毫秒
871.
The finite-difference method is a numerical technique for obtaining approximate solutions to differential equations. The main
objective of the present study is to give a new aspect to the finite-difference method by using a variational derivative.
By applying this formulation, accurate values of the buckling loads of beams and frames with various end supports are obtained.
The performance of this formulation is verified by comparison with numerical examples in the literature
__________
Published in Prikladnaya Mekhanika, Vol. 41, No. 7, pp. 139–144, July 2005. 相似文献
872.
L. B. Beinenson 《Journal of Mathematical Sciences》2005,129(2):3730-3756
For an arbitrary poset H and measure ρ on H × R (where R is the real axis), we construct a monotone decreasing stochastic field ηρ and compute its finite-dimensional distributions. In the case where H is a Λ-semilattice and the measure ρ satisfies additional conditions, we compute various characteristics of the field ηρ such as the expectation of the field value at a point, variance of the field value at a point, and correlation function of the field. The described construction of random fields gives a new method for constructing positive definite functions on posets. Bibliography: 6 titles.__________Translated from Zapiski Nauchnykh Seminarov POMI, Vol. 301, 2003, pp. 92–143. 相似文献
873.
Studies of thickness and temperature dependencies of the dielectric susceptibility of nitrobenzene interlayers formed on conductive substrates were carried out. The obtained data were processed under the assumption of the existence of dimers (with opposite directions of molecular dipole moments) in orientationally ordered wall-adjacent layers. The results were treated on the basis of Lifshits theory. 相似文献
874.
875.
876.
V. I. Deineka 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2006,80(3):429-434
It was demonstrated that the correlations between the logarithms of the retention factors for various pairs of substances being linear makes it possible to plot and analyze maps of separation of complex mixtures at various mobile phase compositions on the basis of two measurements at the boundaries of the eluent composition range. Applied to the available experimental data, the relative analysis of retention showed that the use of incremental relationships in the form of the difference between the retention parameters for the corresponding substances at a given mobile phase composition is incorrect. A substantiation of the new method was presented. 相似文献
877.
I. A. Uspenskaya Z. S. Vakhovskaya M. M. Efremova M. L. Kovba A. L. Emelina Zh. V. Dobrokhotova Yu. V. Goryushkina L. A. Tiflova A. A. Popova A. S. Monaenkova 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2006,80(4):529-534
The thermodynamic properties of the Ln2BaO4 phases (Ln = Dy, Ho, Sm) were studied by the electromotive force method with a fluoride electrolyte (890–1180 K), solution calorimetry in 1.07 N hydrochloric acid at 298.15 K, and differential scanning calorimetry (298–860 K). The experimental data were jointly processed, and the thermodynamic functions of the compounds over the temperature range 298–1200 K were calculated. 相似文献
878.
879.
880.
A. B. Mitkevich 《Mechanics of Composite Materials》2005,41(6):497-504
Errors in the programs of winding pressure vessels can lead to an asymmetric reinforcement structure, which affects the equilibrium
shape of their domes and the tension in the left and right families of filaments. In this paper, equations determining the
equilibrium shape of the domes, the tension in filaments, and the shear stresses between layers are obtained. Examples with
winding trajectories in the form of geodesics and constant-deviation lines are considered. It is found that, for pressure
vessels, in the absence of external torque, the tension levels in filaments of the left and right families differ considerably.
It is also revealed that, for actual friction coefficients in winding, the shear stresses taken up by the binder are insignificant.
__________
Translated from Mekhanika Kompozitnykh Materialov, Vol. 41, No. 6, pp. 743–752, November–December, 2005. 相似文献