全文获取类型
收费全文 | 454104篇 |
免费 | 3780篇 |
国内免费 | 1366篇 |
专业分类
化学 | 226659篇 |
晶体学 | 7064篇 |
力学 | 24028篇 |
综合类 | 14篇 |
数学 | 70036篇 |
物理学 | 131449篇 |
出版年
2019年 | 3551篇 |
2018年 | 14785篇 |
2017年 | 14548篇 |
2016年 | 12652篇 |
2015年 | 4623篇 |
2014年 | 6687篇 |
2013年 | 15993篇 |
2012年 | 15056篇 |
2011年 | 23857篇 |
2010年 | 15782篇 |
2009年 | 16229篇 |
2008年 | 19160篇 |
2007年 | 21269篇 |
2006年 | 12074篇 |
2005年 | 11847篇 |
2004年 | 11376篇 |
2003年 | 10920篇 |
2002年 | 9889篇 |
2001年 | 10913篇 |
2000年 | 8312篇 |
1999年 | 6384篇 |
1998年 | 5323篇 |
1997年 | 5360篇 |
1996年 | 5190篇 |
1995年 | 4644篇 |
1994年 | 4590篇 |
1993年 | 4393篇 |
1992年 | 5100篇 |
1991年 | 5120篇 |
1990年 | 4997篇 |
1989年 | 5081篇 |
1988年 | 4966篇 |
1987年 | 4983篇 |
1986年 | 4634篇 |
1985年 | 6097篇 |
1984年 | 6158篇 |
1983年 | 5156篇 |
1982年 | 5319篇 |
1981年 | 5223篇 |
1980年 | 4965篇 |
1979年 | 5448篇 |
1978年 | 5653篇 |
1977年 | 5670篇 |
1976年 | 5611篇 |
1975年 | 5301篇 |
1974年 | 5130篇 |
1973年 | 5284篇 |
1972年 | 3776篇 |
1968年 | 3376篇 |
1967年 | 3450篇 |
排序方式: 共有10000条查询结果,搜索用时 171 毫秒
991.
G. V. Plyatsko V. N. Maksimovich L. V. Khomlyak 《Journal of Mathematical Sciences》1992,62(1):2518-2523
We solve the thermoplastic problem for a semi-infinite plate under local nonstationary heating by heat sources. The physical equations are taken to be the relations of the nonisothermic theory of plastic flow associated with the Mises fluidity condition. The solution of the problem is constructed by the method of integral equations and the self-correcting method of sequential loading, where time is taken as the loading parameter. We carry out numerical computations of the stresses in the case of heating a plate with heat output by normal-circular heat sources. We study the problem of optimization of heating regimes in order to introduce favorable residual compressive stresses (from the point of view of hardness) in a given region of a half-plane. Two figures.Translated fromMatematicheskie Metody i Fiziko-Mekhanicheskie Polya, Issue 27, 1988, pp. 29–34. 相似文献
992.
993.
994.
H. R. Ebrahimi-Vishki M. A. Pourabdollah 《Proceedings of the American Mathematical Society》1997,125(7):2171-2174
The purpose of this paper is to introduce an algebra of functions on a semitopological semigroup and to study these functions from the point of view of universal semigroup compactification. We show that the corresponding semigroup compactification of this algebra is universal with respect to the property of being a nilpotent group.
995.
996.
A. S. Lobach B. P. Tarasov Yu. M. Shul'ga A. A. Perov A. N. Stepanov 《Russian Chemical Bulletin》1996,45(2):464-465
Fullerene deuteride was obtained by the reaction of deuterium with solid palladium fulleride C60Pd4.9 under fairly mild conditions. The compound was identified by FD-MS, UV-Vis and IR spectroscopies, and TLC.Translated from Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 483–484, February, 1996 相似文献
997.
This work is devoted to the numerical solution of the Navier–Stokes equations for compressible viscous fluids. Finite element approximations and stabilization techniques are addressed. We present methods to implement discontinuous approximations for the pressure and the density. An upwinding methodology is being investigated which combines the ideas behind the stream line Petrov–Galerkin method and the flux limiter methods aiming to introduce numerical diffusion only where it is necessary. 相似文献
998.
The equilibrium and rate of solvent extraction of zinc chloride complexes from HCl solutions into benzene solutions of tributyl phosphate (TBP) have been studied. The extracted species are discussed in the light of the results. The extraction was found to be first order with respect to both Zn(II) and TBP, and zero order for HCl. The rate-controlling steps are discussed and the rate constants for these reactions are calculated. 相似文献
999.
1000.
Alexander N Shivanyuk Dmitry M Rudkevich David N Reinhoudt 《Tetrahedron letters》1996,37(52):9341-9344
An assembly of cation receptor 1 and anion receptor 2 via the hydrogen bonding melamine-barbiturate structural motif complexes sodium thiocyanate, sodium iodide, and sodium azide in apolar solvents. 相似文献