全文获取类型
收费全文 | 4617篇 |
免费 | 135篇 |
国内免费 | 38篇 |
专业分类
化学 | 2850篇 |
晶体学 | 10篇 |
力学 | 170篇 |
数学 | 947篇 |
物理学 | 813篇 |
出版年
2023年 | 28篇 |
2022年 | 100篇 |
2021年 | 97篇 |
2020年 | 107篇 |
2019年 | 92篇 |
2018年 | 92篇 |
2017年 | 70篇 |
2016年 | 185篇 |
2015年 | 152篇 |
2014年 | 185篇 |
2013年 | 289篇 |
2012年 | 323篇 |
2011年 | 331篇 |
2010年 | 160篇 |
2009年 | 202篇 |
2008年 | 278篇 |
2007年 | 269篇 |
2006年 | 235篇 |
2005年 | 214篇 |
2004年 | 211篇 |
2003年 | 156篇 |
2002年 | 108篇 |
2001年 | 54篇 |
2000年 | 42篇 |
1999年 | 36篇 |
1998年 | 42篇 |
1997年 | 40篇 |
1996年 | 57篇 |
1995年 | 23篇 |
1994年 | 42篇 |
1993年 | 47篇 |
1992年 | 58篇 |
1991年 | 23篇 |
1990年 | 27篇 |
1989年 | 22篇 |
1988年 | 22篇 |
1987年 | 19篇 |
1986年 | 18篇 |
1985年 | 42篇 |
1984年 | 34篇 |
1983年 | 30篇 |
1982年 | 36篇 |
1981年 | 17篇 |
1980年 | 21篇 |
1979年 | 20篇 |
1978年 | 23篇 |
1977年 | 17篇 |
1976年 | 15篇 |
1974年 | 14篇 |
1973年 | 12篇 |
排序方式: 共有4790条查询结果,搜索用时 15 毫秒
81.
82.
A Lie group is called quadratic if it carries a bi-invariant semi-Riemannian metric. Oscillator Lie groups constitute a subclass of the class of quadratic Lie groups. In this paper, we determine the Lie bialgebra structures and the solutions of the classical Yang–Baxter equation on a generic class of oscillator Lie algebras. Moreover, we show that any solution of the generalized classical Yang–Baxter equation (resp. classical Yang–Baxter equation) on a quadratic Lie group determines a left invariant locally symmetric (resp. flat) semi-Riemannian metric on the corresponding dual Lie groups. 相似文献
83.
Gustavo Forte Alberto Lencina Myrian Tebaldi Néstor Bolognini 《Optics Communications》2011,284(10-11):2494-2499
The self-image phenomenon by a volume grating is proposed and theoretically analyzed. A theoretical model based on a path integral formulation to describe wave propagation through the grating inhomogeneous medium is applied. A modified version of the scalar diffraction theory Fresnel propagator is obtained which allows calculating the diffracted field amplitude by the grating. The proposed model is applied to amplitude and/or phase volume gratings. Remarkable features appear, in particular at the fractional Talbot distance 0.125zT. In this case, if an in-phase real and imaginary grating modulation is considered a self-image intensity profile is observed for determined values of the absorptive and refractive parameters. On the other hand, a spatial comb intensity profile for a near half period shift between the real and imaginary grating modulations is found. 相似文献
84.
Ivanovskaya VV Zobelli A Wagner P Heggie MI Briddon PR Rayson MJ Ewels CP 《Physical review letters》2011,107(6):065502
We demonstrate that free graphene sheet edges can curl back on themselves, reconstructing as nanotubes. This results in lower formation energies than any other nonfunctionalized edge structure reported to date in the literature. We determine the critical tube size and formation barrier and compare with density functional simulations of other edge terminations including a new reconstructed Klein edge. Simulated high resolution electron microscopy images show why such rolled edges may be difficult to detect. Rolled zigzag edges serve as metallic conduction channels, separated from the neighboring bulk graphene by a chain of insulating sp(3)-carbon atoms, and introduce van Hove singularities into the graphene density of states. 相似文献
85.
Alberto Dolcetti 《Annali dell'Universita di Ferrara》1989,35(1):17-23
Riassunto Se il genere è alto, le curve di rango massimo sono proiettivamente normali. La nozione di ?genere alto? è precisata fornendo
un limite explicito, dipendente solo dal grado.
Dal 14 giugno 1990: Dip. di Matematica ?U. Dini?, viale Morgagni 67/A, 50134 Firenze. 相似文献
Summary Maximal rank space curves of high genus are projectively normal. We precise the meaning of ?high genus?, by giving an explicit bound, depending only on the degree.
Dal 14 giugno 1990: Dip. di Matematica ?U. Dini?, viale Morgagni 67/A, 50134 Firenze. 相似文献
86.
87.
Vittorio Gorini Alberto Frigerio Maurizio Verri Andrzej Kossakowski E.C.G. Sudarshan 《Reports on Mathematical Physics》1978,13(2):149-173
In this paper we give an essentially self-contained account of some general structural properties of the dynamics of quantum open Markovian systems. We review some recent results regarding the problem of the classification of quantum Markovian master equations and the limiting conditions under which the dynamical evolution of a quantum open system obeys an exact semigroup law (weak coupling limit and singular coupling limit). We discuss a general form of quantum detailed balance and its relation to thermal relaxation and to microreversibility. 相似文献
88.
We construct quantum stochastic processes whose multi-time correlation functions, with suitable time ordering, can be obtained from a quantum dynamical semigroup. We prove that such a process defines a stationary Markov dilation of the associated semigroup if and only if (up to technicalities) the semigroup satisfies the quantum detailed balance condition with respect to its stationary state. 相似文献
89.
90.
D. Hojman M. A. Cardona D. Bazzacco N. Blasi J. Davidson M. Davidson M. E. Debray A. J. Kreiner S. M. Lenzi G. Lo Bianco D. R. Napoli C. Rossi Alvarez 《The European Physical Journal A - Hadrons and Nuclei》2004,21(3):383-390
High-spin states in 163,164Ho were investigated by means of in-beam
-ray spectroscopy techniques using the multidetector array GASP. Excited states in 163,164Ho were populated predominantly through the incomplete-fusion mechanism in the 160Gd (11B
reaction at a beam energy of 61 MeV. Known rotational bands in 163
Ho have been extended to higher spins and a three-quasiparticle band has been observed in this nucleus. Rotational bands have been identified in 164Ho and their configurations have been discussed. Empirical Gallagher-Moszkowski (GM) splitting energies were extracted from the
and
GM doublets. Alignments, band crossing frequencies, and electromagnetic properties have been analyzed in the framework of the cranking model.Received: 13 February 2004, Revised: 18 March 2004, Published online: 14 September 2004PACS:
21.10.Re Collective levels - 21.60.Ev Collective models - 23.20.Lv
transitions and level energies - 27.70. + q
相似文献