全文获取类型
收费全文 | 465727篇 |
免费 | 6470篇 |
国内免费 | 1380篇 |
专业分类
化学 | 251350篇 |
晶体学 | 6695篇 |
力学 | 19467篇 |
综合类 | 18篇 |
数学 | 55295篇 |
物理学 | 140752篇 |
出版年
2021年 | 4009篇 |
2020年 | 4573篇 |
2019年 | 4836篇 |
2018年 | 6242篇 |
2017年 | 6110篇 |
2016年 | 9609篇 |
2015年 | 6171篇 |
2014年 | 9232篇 |
2013年 | 21623篇 |
2012年 | 16942篇 |
2011年 | 20635篇 |
2010年 | 14457篇 |
2009年 | 14142篇 |
2008年 | 18884篇 |
2007年 | 18735篇 |
2006年 | 17380篇 |
2005年 | 15557篇 |
2004年 | 14464篇 |
2003年 | 12652篇 |
2002年 | 12410篇 |
2001年 | 13972篇 |
2000年 | 10600篇 |
1999年 | 8278篇 |
1998年 | 6920篇 |
1997年 | 6636篇 |
1996年 | 6510篇 |
1995年 | 5842篇 |
1994年 | 5821篇 |
1993年 | 5618篇 |
1992年 | 6282篇 |
1991年 | 6217篇 |
1990年 | 5977篇 |
1989年 | 5772篇 |
1988年 | 5804篇 |
1987年 | 5686篇 |
1986年 | 5395篇 |
1985年 | 6950篇 |
1984年 | 7106篇 |
1983年 | 5603篇 |
1982年 | 5707篇 |
1981年 | 5693篇 |
1980年 | 5285篇 |
1979年 | 5671篇 |
1978年 | 5788篇 |
1977年 | 5684篇 |
1976年 | 5627篇 |
1975年 | 5200篇 |
1974年 | 5159篇 |
1973年 | 5124篇 |
1972年 | 3605篇 |
排序方式: 共有10000条查询结果,搜索用时 203 毫秒
931.
A.M. van der Kraan 《Hyperfine Interactions》1998,111(1-4):23-34
In modern society the application of catalysts, and hence, research in the field of catalysis, is becoming more and more important. In the strongly increasing chemical industry most reaction processes are performed with the aid of catalysts. Knowledge about the structure of the active sites present at the surface of catalysts will facilitate the design of new catalysts with better performances. Such knowledge can be obtained by Mössbauer spectroscopy, which is an excellent in-situ characterization technique due to the high penetrating power of the γ-radiation used and the sensitivity of the spectral parameters for the chemical state and local environment of the Mössbauer atoms. 相似文献
932.
933.
T. N. Mamedov V. N. Duginov A. V. Stoykov I. L. Chaplygin D. Herlach U. Zimmermann V. N. Gorelkin J. Major M. Schefzik 《JETP Letters》1998,68(1):64-70
The residual polarization of negative muons in crystal silicon samples with phosphorus (P: 1.6×1013 cm−3) and antimony (Sb: 2×1018 cm−3) impurities is investigated. The measurements are made in a 1000 G magnetic field oriented in a direction transverse to the
muon spin in the temperature range 4–300 K. The relaxation rate and shift of the precession frequency in the silicon sample
with the phosphorus impurity are measured more accurately than previously. It is found that in antimony-doped silicon the
acceptor center
μ
A1 at temperatures below 30 K can be in both ionized and neutral states. The experimental data are interpreted on the basis
of spin-lattice relaxation of the magnetic moment of an acceptor center, formation of acceptor-donor pairs, and recombination
of charge carriers at the acceptor. Preliminary measurements showed a nonzero residual polarization of negative muons in germanium.
Pis’ma Zh. éksp. Teor. Fiz. 68, No. 1, 61–66 (10 July 1998) 相似文献
934.
A dual Ginzburg-Landau model corresponding to SU(3) gluodynamics in the Abelian projection is studied. A string theory describing QCD string dynamics is obtained in this
model. The interaction of static quarks in mesons and baryons is investigated in an approximation to leading order.
Pis’ma Zh. éksp. Teor. Fiz. 68, No. 2, 109–114 (25 July 1998) 相似文献
935.
S. M. Stishov 《JETP Letters》1998,67(1):90-94
Explanations are given for why there is no real first-order phase transition in the one-component plasma (OCP) model. The
fluid (liquid) and crystalline states of the OCP observed in computer experiments are not in equilibrium, on account of instability
of the system. However, specific features of the free energy suggest that some sort of a “virtual” phase transition occurs
in the model. Such a transition can be turned real by choosing the right form of the background energy.
Pis’ma Zh. éksp. Teor. Fiz. 67, No. 1, 82–85 (10 January 1997)
Published in English in the original Russian journal. Edited by Steve Torstveit. 相似文献
936.
The nearest-neighbor two-point correlation function of the Z-invariant inhomogeneous eight-vertex model in the thermodynamic limit is computed using the free-field representation.
Pis’ma Zh. éksp. Teor. Fiz. 68, No. 3, 243–247 (10 August 1998)
Published in English in the original Russian journal. Edited by Steve Torstveit. 相似文献
937.
The anomalous proximity effect between a d-wave superconductor and a thin disordered normal layer is studied theoretically in the framework of Eilenberger equations.
It is shown that disorder of the quasiparticle reflection from this thin layer leads to the formation of an s-wave component localized near the boundary. The angular and spatial structure of the pair potential near the interface is
studied.
Pis’ma Zh. éksp. Teor. Fiz. 67, No. 7, 478–483 (10 April 1998)
Published in English in the original Russian journal. Edited by Steve Torstveit. 相似文献
938.
S. Pumplün 《manuscripta mathematica》1998,97(1):93-108
For a Brauer–Severi variety X over a field k of characteristic not two, every symmetric bilinear space over X up to Witt equivalence is defined over k.
Received: 2 February 1998 相似文献
939.
C. A. Lütken 《Journal of statistical physics》1995,78(1-2):441-451
Charge transport in two dimensions provides an ideal laboratory for investigating parameter space geometries. The Onsager relations for anisotropic transport in a parity-violating external field endow these spaces with a highly nontrivial complex (and Kähler) structure, which can be given a simple geometrical interpretation. A large class of Coulomb gases exhibiting this structure have a generalized Kramers-Wannier symmetry (complexfield duality) which is contained in the modular group. Knowledge of this symmetry and the degrees of freedom encoded in the Coulomb gas appear to be sufficient to determine the global phase diagram and the renormalization group fixed-point structure, including the critical exponents. This accounts for all the scaling behavior observed so far in the quantum Hall system. 相似文献
940.
In this paper we show that the Boltzmann weights of the three-dimensional Baxter-Bazhanov model give representations of the braid group if some suitable spectral limits are taken. In the trigonometric case we classify all possible spectral limits which produce braid group representations. Furthermore, we prove that for some of them we get cyclotomic invariants of links and for others we obtain tangle invariants generalizing the cyclotomic ones. 相似文献