全文获取类型
收费全文 | 220934篇 |
免费 | 2698篇 |
国内免费 | 1324篇 |
专业分类
化学 | 122730篇 |
晶体学 | 3228篇 |
力学 | 8891篇 |
综合类 | 61篇 |
数学 | 24365篇 |
物理学 | 65681篇 |
出版年
2020年 | 1754篇 |
2019年 | 1896篇 |
2018年 | 2483篇 |
2017年 | 2531篇 |
2016年 | 3645篇 |
2015年 | 2424篇 |
2014年 | 3537篇 |
2013年 | 8876篇 |
2012年 | 7686篇 |
2011年 | 9396篇 |
2010年 | 6649篇 |
2009年 | 6452篇 |
2008年 | 8792篇 |
2007年 | 8902篇 |
2006年 | 8384篇 |
2005年 | 7706篇 |
2004年 | 6870篇 |
2003年 | 6055篇 |
2002年 | 5985篇 |
2001年 | 6703篇 |
2000年 | 5067篇 |
1999年 | 3669篇 |
1998年 | 3038篇 |
1997年 | 3008篇 |
1996年 | 3011篇 |
1995年 | 2618篇 |
1994年 | 2718篇 |
1993年 | 2582篇 |
1992年 | 2829篇 |
1991年 | 2894篇 |
1990年 | 2703篇 |
1989年 | 2616篇 |
1988年 | 2558篇 |
1987年 | 2497篇 |
1986年 | 2520篇 |
1985年 | 3300篇 |
1984年 | 3359篇 |
1983年 | 2804篇 |
1982年 | 3046篇 |
1981年 | 2811篇 |
1980年 | 2607篇 |
1979年 | 2790篇 |
1978年 | 2996篇 |
1977年 | 3032篇 |
1976年 | 3059篇 |
1975年 | 2793篇 |
1974年 | 2906篇 |
1973年 | 2956篇 |
1972年 | 2318篇 |
1971年 | 1845篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
121.
É. L. Nagaev 《Physics of the Solid State》1997,39(9):1415-1419
The temperature peak of the resistance and the giant magnetoresistance of degenerate ferromagnetic semiconductors with an
arbitrary degree of electron spin polarization are investigated. The spin-wave and paramagnetic domains are considered. The
calculations are based on the notion of the magnetic-impurity scattering of carriers.
Fiz. Tverd. Tela (St. Petersburg) 39, 1589–1593 (September 1997) 相似文献
122.
S. M. Dunaevskii A. L. Malyshev V. A. Trunov V. V. Popov 《Physics of the Solid State》1997,39(10):1636-1637
The results of investigating the temperature dependence of the resistivity, the differential magnetic susceptibility, and
the magnetoresistance of a partially substituted perovskite Sm1−x
SrxMnO3 (x=0.16–0.4) are presented. Colossal intrinsic magnetoresistance, reaching 90% in an external magnetic field of 30 kOe, is discovered
in the compound with x=0.30 at 77 K.
Fiz. Tverd. Tela (St. Petersburg) 39, 1831–1832 (October 1997) 相似文献
123.
124.
125.
L. Bugliaro J. Fröhlich G.M. Graf J. Stubbe C. Fefferman 《Communications in Mathematical Physics》1997,187(3):567-582
A Lieb-Thirring-Sobolev type inequality for Pauli Hamiltonians with magnetic fields is derived. The bound is in terms of an
effective field, whose energy is comparable to that of the magnetic field itself. An application to the stability of matter
in magnetic fields is given.
Received: 19 September 1996 / Accepted: 3 January 1997 相似文献
126.
No analytic solutions of the Schrödinger equation are known for the quartic anharmonic oscillator. We show in this paper that there are closely related modified quartic oscillators with the potential depending on |x| for which analytic solutions for some states exist. These results can be extended to the higher order oscillators 相似文献
127.
128.
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
129.
We show that “top-down” mechanisms of ultrahigh-energy cosmic rays which involve heavy relic particle-like objects predict
a Galactic anisotropy of the highest-energy cosmic rays at the level of minimum ∼ 20%. This anisotropy is large enough to
be either observed or ruled out in the next generation of experiments.
Pis’ma Zh. éksp. Teor. Fiz. 68, No. 2, 99–103 (25 July 1998)
Published in English in the original Russian journal. Edited by Steve Torstveit. 相似文献
130.
We show that an electron confined to a single finite parabolic quantum well in crossed electric and magnetic fields can behave as a double quantum well system. The magnetic field is parallel to the heterostructure layers and the electric field is perpendicular to those. For a suitable choice of both fields and quantum well width, the electron can be confined to a double quantum well effective potential that is very similar to the electronic potential model for diatomic molecules. The double quantum well spectrum is calculated using a numerical algorithm based on semiclassical methods. A physical interpretation of this quantum system is given based on the analogy to the electrons bound to diatomic molecules. 相似文献