全文获取类型
收费全文 | 348291篇 |
免费 | 4321篇 |
国内免费 | 1151篇 |
专业分类
化学 | 190438篇 |
晶体学 | 5681篇 |
力学 | 14709篇 |
综合类 | 18篇 |
数学 | 35632篇 |
物理学 | 107285篇 |
出版年
2021年 | 2313篇 |
2020年 | 2680篇 |
2019年 | 2939篇 |
2018年 | 3245篇 |
2017年 | 3348篇 |
2016年 | 5550篇 |
2015年 | 3873篇 |
2014年 | 5709篇 |
2013年 | 15778篇 |
2012年 | 11945篇 |
2011年 | 14848篇 |
2010年 | 9851篇 |
2009年 | 10048篇 |
2008年 | 13436篇 |
2007年 | 13331篇 |
2006年 | 12681篇 |
2005年 | 11590篇 |
2004年 | 10528篇 |
2003年 | 9368篇 |
2002年 | 9057篇 |
2001年 | 11031篇 |
2000年 | 8408篇 |
1999年 | 6417篇 |
1998年 | 4974篇 |
1997年 | 4947篇 |
1996年 | 4792篇 |
1995年 | 4380篇 |
1994年 | 4181篇 |
1993年 | 3921篇 |
1992年 | 4804篇 |
1991年 | 4697篇 |
1990年 | 4401篇 |
1989年 | 4400篇 |
1988年 | 4428篇 |
1987年 | 4387篇 |
1986年 | 4169篇 |
1985年 | 5710篇 |
1984年 | 5708篇 |
1983年 | 4527篇 |
1982年 | 4767篇 |
1981年 | 4727篇 |
1980年 | 4483篇 |
1979年 | 4732篇 |
1978年 | 4827篇 |
1977年 | 4883篇 |
1976年 | 4689篇 |
1975年 | 4412篇 |
1974年 | 4304篇 |
1973年 | 4317篇 |
1972年 | 2777篇 |
排序方式: 共有10000条查询结果,搜索用时 234 毫秒
171.
The three-band two-dimensional repulsive Hubbard model in the formalism of the temperature Green function is investigated.
The applicability of the weak coupling approach at the values of the dimensionless coupling constant U/t≈10–11 is justified.
The normal state, the antiferromagnetic state with Neel magnetic ordering on the “copper” sublattice, and the superconducting
state with nontrivial Cooper pairing in channels with odd angular momenta are studied. The possibility of other magnetic states
in the model is discussed. Bibliography: 20 titles.
Translated fromZapiski Nauchnykh Seminarov POMI, Vol. 209, 1994, pp. 194–228.
Translated by K. Malyshev. 相似文献
172.
C. W. LEUNG Department of Mathematics The Chinese Universityof Hong Kong Shatin. N. T. Hong Kong China. 《数学年刊B辑(英文版)》1997,(1)
ASTRASSENLAWOFTHEITERATEDLOGARITHMFORPROCESSESWITHINDEPENDENTINCREMENTWangJiagangAbstractLetX={X(t),t0}beaproceswithindep... 相似文献
173.
A. K. Lopatin 《Ukrainian Mathematical Journal》1997,49(1):51-74
We consider the method of normal forms, the Bogolyubov averaging method, and the method of asymptotic decomposition proposed by Yu. A. Mitropol’skii and the author of this paper. Under certain assumptions about group-theoretic properties of a system of zero approximation, the results obtained by the method of asymptotic decomposition coincide with the results obtained by the method of normal forms or the Bogolyubov averaging method. We develop a new algorithm of asymptotic decomposition by a part of the variables and its partial case — the algorithm of averaging on a compact Lie group. For the first time, it became possible to consider asymptotic expansions of solutions of differential equations on noncommutative compact groups. 相似文献
174.
175.
176.
177.
178.
179.
A. J. Parsons S. D. J. Inglethorpe D. J. Morgan A. C. Dunham 《Journal of Thermal Analysis and Calorimetry》1997,48(1):49-62
Using a system based on non-dispersive infrared (NDIR) detectors, evolved gas analysis (EGA) was able to identify and quantify the principal volatiles produced by heating powdered samples of UK brick clays. From these results, atmospheric emissions likely to result from brick production can be predicted. In addition, EGA results for extruded brick clay test pieces are significantly different from those of powdered samples. Within an extruded brick clay body, evolved gases are contained within a pore system and evolved gas-solid phase reactions also occur. This EGA study provides further evidence on the nature of firing reactions within brick clay bodies. The qualitative and quantitative influence of heating rate — a key process condition in brick manufacture — on gas release is also outlined.Dedicated to Dr. Robert Mackenzie on the occasion of his 75th birthday 相似文献
180.
R.C. Viscovini E.M. Telles A. Scalabrin D. Pereira 《Applied physics. B, Lasers and optics》1997,65(1):33-35
2 laser of wide tunability to pump 13CD3OD we could observe 10 new far infrared laser lines ranging from 109 μm to 472 μm. The lines were generated by pumping infrared
absorbing transitions of large offset appertaining to the C-O stretching Q-branch. All lines were characterised in wavelength,
polarisation, optimum pressure of operation and precise offset measurements.
Received: 17 September 1996/Revised version: 18 November 1996 相似文献