全文获取类型
收费全文 | 559篇 |
免费 | 0篇 |
专业分类
化学 | 444篇 |
晶体学 | 13篇 |
力学 | 7篇 |
数学 | 14篇 |
物理学 | 81篇 |
出版年
2022年 | 8篇 |
2021年 | 13篇 |
2020年 | 9篇 |
2019年 | 11篇 |
2018年 | 23篇 |
2017年 | 16篇 |
2016年 | 18篇 |
2015年 | 6篇 |
2014年 | 8篇 |
2013年 | 31篇 |
2012年 | 32篇 |
2011年 | 23篇 |
2010年 | 27篇 |
2009年 | 17篇 |
2008年 | 20篇 |
2007年 | 14篇 |
2006年 | 23篇 |
2005年 | 20篇 |
2004年 | 18篇 |
2003年 | 22篇 |
2002年 | 17篇 |
2001年 | 16篇 |
2000年 | 9篇 |
1999年 | 7篇 |
1997年 | 4篇 |
1995年 | 3篇 |
1994年 | 6篇 |
1993年 | 8篇 |
1991年 | 6篇 |
1989年 | 3篇 |
1988年 | 8篇 |
1987年 | 10篇 |
1986年 | 8篇 |
1985年 | 3篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1982年 | 3篇 |
1981年 | 5篇 |
1979年 | 6篇 |
1978年 | 3篇 |
1977年 | 3篇 |
1976年 | 3篇 |
1974年 | 7篇 |
1973年 | 7篇 |
1972年 | 6篇 |
1971年 | 8篇 |
1970年 | 8篇 |
1969年 | 5篇 |
1968年 | 3篇 |
1961年 | 2篇 |
排序方式: 共有559条查询结果,搜索用时 15 毫秒
1.
Russian Physics Journal - Using the potentials, generated by a tight binding approximation, the equilibrium atomic structure and the phonon spectra of Cr and Ni thin films (one monolayer) deposited... 相似文献
2.
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
3.
Grigor'ev S. A. Kalinnikov A. A. Porembskii V. I. Baranov I. E. Borisova E. V. Fateev V. N. 《Russian Journal of Electrochemistry》2004,40(11):1188-1192
A two-dimensional mathematical model for the transport of reactants in a fuel cell with a solid polymer electrolyte is developed. The model is used for analyzing spatial distributions of the concentration of reactants and current density over the cell. The effect of the catalytic-layer activity, reactant speed, bipolar-plate geometry, thickness and porosity of current collector and/or gas-diffusion sublayer, and the reaction mixture composition on the fuel cell efficiency is estimated theoretically and experimentally. 相似文献
4.
JOSEF MÁLEK JINDŘICH NEČAS K. R. RAJAGOPAL 《Archive for Rational Mechanics and Analysis》2002,165(3):243-269
To describe the flows of fluids over a wide range of pressures, it is necessary to take into account the fact that the viscosity
of the fluid depends on the pressure. That the viscosity depends on the pressure has been verified by numerous careful experiments.
While the existence of solutions local-in-time to the equations governing the flows of such fluids are available for small,
special data and rather unrealistic dependence of the viscosity on the pressure, no global existence results are in place.
Our interest here is to establish the existence of weak solutions for spatially periodic three-dimensional flows that are
global in time, for a large class of physically meaningful viscosity-pressure relationships.
(Accepted May 1, 2002) Published online November 15, 2002
Communicated by S. S. ANTMAN 相似文献
5.
6.
7.
8.
9.
Summary Halogen derivatives of the N-alkylmonoamides and N-alkylimides of maleic and citraconic acid containing the strongly electronegative group CF3 in the alkyl radical, previously unreported in the literature, have been synthesized. 相似文献
10.
Synthesis and nitration of NH- and N-vinyl-4,5,7-trimethyl-4,5,6,7-tetrahydropyrrolo[3,2-c]pyridines
T. N. Borisova I. A. Stazharova A. É. Aliev N. S. Prostakov A. V. Varlamov 《Chemistry of Heterocyclic Compounds》1991,27(10):1105-1109
It has been shown that the most efficient catalysts for the synthesis of 4,5,7-trimethyl-4,5,6,7-tetrahydropyrrolo[3,2-c]pyridine from 1,2,5-trimethylpyridin-4-one and acetylene under Trofimov conditions are rubidium and potassium hydroxides. Use of Triton B or a mixture of trimethylbenzylammonium chloride with rubidium hydroxide as catalyst gives O-alkylated oxime. Their configurations and conformations were established through separation of the individual isomers of 1-vinyl-4,5,7-trimethyl-4,5,6,7-tetrahydropyrrolo[3,2-c]pyridines. Acetyl nitrate nitration of the cis isomer of this compound gave the 2- and 3-nitro derivatives. Similar nitration of 4,5,7-trimethyl-4,5,6,7-tetrahydropyrrolo[3,2-c]pyridine gave the 2-nitro-7-hydroxy derivative.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1375–1380, October, 1991. 相似文献