全文获取类型
收费全文 | 2031篇 |
免费 | 11篇 |
国内免费 | 2篇 |
专业分类
化学 | 1048篇 |
晶体学 | 24篇 |
力学 | 52篇 |
数学 | 182篇 |
物理学 | 738篇 |
出版年
2021年 | 40篇 |
2020年 | 26篇 |
2019年 | 39篇 |
2018年 | 43篇 |
2017年 | 51篇 |
2016年 | 70篇 |
2015年 | 28篇 |
2014年 | 48篇 |
2013年 | 82篇 |
2012年 | 68篇 |
2011年 | 91篇 |
2010年 | 80篇 |
2009年 | 74篇 |
2008年 | 86篇 |
2007年 | 78篇 |
2006年 | 64篇 |
2005年 | 61篇 |
2004年 | 55篇 |
2003年 | 48篇 |
2002年 | 56篇 |
2001年 | 43篇 |
2000年 | 40篇 |
1999年 | 38篇 |
1998年 | 20篇 |
1997年 | 27篇 |
1996年 | 22篇 |
1995年 | 19篇 |
1994年 | 26篇 |
1993年 | 20篇 |
1992年 | 31篇 |
1991年 | 21篇 |
1990年 | 26篇 |
1989年 | 22篇 |
1988年 | 23篇 |
1987年 | 29篇 |
1986年 | 21篇 |
1983年 | 20篇 |
1982年 | 22篇 |
1980年 | 21篇 |
1979年 | 18篇 |
1978年 | 36篇 |
1977年 | 22篇 |
1976年 | 18篇 |
1975年 | 24篇 |
1974年 | 26篇 |
1973年 | 21篇 |
1972年 | 18篇 |
1971年 | 18篇 |
1968年 | 20篇 |
1967年 | 18篇 |
排序方式: 共有2044条查询结果,搜索用时 968 毫秒
111.
Tunneling of electrons with conservation of the transverse wave vector in the Au/CaF2/Si(111) system
M. I. Vexler Yu. Yu. Illarionov S. M. Suturin V. V. Fedorov N. S. Sokolov 《Physics of the Solid State》2010,52(11):2357-2363
Epitaxial layers of calcium fluoride on silicon(111) have been prepared, in which tunneling transfer of electrons with conservation
of the transverse momentum component has been observed. A good agreement between the results of simulation and the experimental
data has been achieved. The procedure underlying the calculations has been described in detail. The obtained films are suitable
for the use as barrier layers in various solid-state electronic devices. 相似文献
112.
113.
Juan A. Colón Santana V. Singh V. Palshin E. M. Handberg A. G. Petukhov Y. B. Losovyj A. Sokolov Ihor Ketsman 《Applied Physics A: Materials Science & Processing》2010,98(4):811-819
We have characterized the local structure around the Cr atom, as a function of Cr content, in films of chromium-doped hydrogenated
amorphous diamond-like carbon (Cr-DLC) synthesized by plasma-enhanced chemical vapor deposition (PECVD). The composition appears
to be related to the structure and forward bias magnetoresistance in heterojunction devices. Chromium in diamond-like carbon
(DLC) has a chemical state much like chromium carbide and, at low Cr content, the Cr is dissolved in an amorphous DLC matrix
forming an atomic-scale composite. At higher Cr content, Cr is present as nano-composite and chromium carbide precipitates
preferentially form at the surface of the film. In these films of higher chromium concentration, a large coefficient of negative
magnetoresistance is observed in heterojunction devices with n-type silicon. 相似文献
114.
L. Haeggqwist L. Schimansky-Geier I. M. Sokolov F. Moss 《The European physical journal. Special topics》2008,157(1):33-42
We study the diffusion coefficient of Active Brownian particles in
two dimensions. In addition to usual attributes of active motion we
let the particles turn in preferred directions over random times.
This angular motion is modeled by an effective Lorentz force with
time dependent frequency switching between two values at
exponentially distributed random times. The diffusion coefficient is
calculated by the Taylor-Kubo formula where distributions found from
a Fokker-Planck equation or from a continuous time random walk
approach have been inserted for averaging. Eventually properties
of the diffusion coefficient will be discussed. 相似文献
115.
U. V. Valiev D. R. Dzhuraev S. I. Mukhamedkhanova N. M. Narzullaev V. Yu. Sokolov S. A. Rakhimov 《Russian Physics Journal》2008,51(6):593-600
The Zeeman effect is investigated in the green luminescence band corresponding to the 4f→4f radiative transition 5D4 → 7F5 of Tb
3+
ions in Tb
0.2
Y
2.8
A
l5
O
12
terbium-yttrium-aluminum garnet at the temperature T = 85 K. It is demonstrated that an external field causes not only the
Zeeman shifts of the resonant frequencies of radiative transitions in the luminescence spectra but also changes in the emission
line intensities caused by modification of the optical transition probabilities in the σ− and σ+ opposite circular polarization states. Special features of field dependences of the Zeeman effect for the emission lines
are qualitatively explained based on the results of numerical energy spectrum calculations for the 5D4 and 7F5 multiplets of the Tb
3+
ion in yttrium-aluminum garnet in the geometry of the longitudinal and transverse Zeeman effects. The possibility of nonequilibrium
population of sublevels of the (Γ1, Γ4) quasi-doublet state of the 5D4 multiplet with energy of ∼20585 cm−1 is demonstrated in an external magnetic field.
__________
Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 6, pp. 38–45, June, 2008. 相似文献
116.
117.
Koga T Seo YS Zhang Y Shin K Kusano K Nishikawa K Rafailovich MH Sokolov JC Chu B Peiffer D Occhiogrosso R Satija SK 《Physical review letters》2002,89(12):125506
We report an anomalous swelling of polymer thin films in carbon dioxide (CO(2)) which is associated (in both locus and form) with the density fluctuation ridge that forms along the extension of the coexistence curve of gas and liquid in the P-T phase diagram. Neutron reflectivity results showed that CO(2) could be sorbed to a large extent ( approximately 60%) in thin polymer films even when the bulk miscibility of the polymer with CO(2) is very poor. The anomalous swelling is found to scale with the polymer radius of gyration (R(g)) and extends to a distance approximately 10 R(g). 相似文献
118.
For 3-manifolds, we define an invariant t(M)=a+bε, where a,b are integers and
. An advantage of the invariant is that it admits a very simple interpretation in terms of a fake surface and a simple geometric
proof of the invariance. Actually, it coincides with the homologically trivial part of the Turaev-Viro invariant of degree
r=5. Extensive tables for all closed irreducible orientable 3-manifolds of complexity less than or equal to six are explicitly
presented. Similar tables for r=3,4 were composed by L. H. Kauffman and S. Lins. Bibliography: 8 titles.
Published inZapiski Nauchnykh Seminarov POMI, Vol. 234, 1996, pp. 137–142. 相似文献
119.
Sokolov IM 《Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics》1999,60(3):3402-3404
We consider the Pope-Ching differential equation [Phys. Fluids A 5, 1529 (1993)] connecting the probability density p(x)(x) of a stationary, homogeneous stochastic process x(t) and the conditional moments of its squared velocity and acceleration. We show that the solution of the Pope-Ching equation can be expressed as n(x), where n(x) is the mean number of crossings of the x level per unit time and is the mean inverse velocity of crossing. This result shows that the probability density at x is fully determined by a one-point measurement of crossing velocities, and does not imply knowledge of the x(t) behavior outside of the infinitesimally narrow window near x. 相似文献
120.
Skiff N. Sokolov 《Reports on Mathematical Physics》1984,20(2):235-246
We find explicitly in the p-representation the kernels of the logarithms of unitary operators transforming the free Hamiltonian into the general solution of the one-channel inverse scattering problem, when bound states are absent. Then we construct the transformation of the Hamiltonian adding to its spectrum the given set of bound states without changing the scattering operator. Other generators of the Poincaré group are constructed in a similar way. The proof of some relevant limits is given. 相似文献