全文获取类型
收费全文 | 280753篇 |
免费 | 1675篇 |
国内免费 | 535篇 |
专业分类
化学 | 129884篇 |
晶体学 | 4011篇 |
力学 | 14857篇 |
综合类 | 9篇 |
数学 | 42698篇 |
物理学 | 91504篇 |
出版年
2019年 | 1444篇 |
2018年 | 10623篇 |
2017年 | 11452篇 |
2016年 | 7068篇 |
2015年 | 2747篇 |
2014年 | 3138篇 |
2013年 | 7786篇 |
2012年 | 10380篇 |
2011年 | 19883篇 |
2010年 | 12406篇 |
2009年 | 12542篇 |
2008年 | 17388篇 |
2007年 | 20861篇 |
2006年 | 6730篇 |
2005年 | 12768篇 |
2004年 | 8742篇 |
2003年 | 8052篇 |
2002年 | 6086篇 |
2001年 | 5631篇 |
2000年 | 4446篇 |
1999年 | 3302篇 |
1998年 | 2800篇 |
1997年 | 2712篇 |
1996年 | 2593篇 |
1995年 | 2414篇 |
1994年 | 2371篇 |
1993年 | 2156篇 |
1992年 | 2484篇 |
1991年 | 2606篇 |
1990年 | 2385篇 |
1989年 | 2358篇 |
1988年 | 2345篇 |
1987年 | 2240篇 |
1986年 | 2100篇 |
1985年 | 2674篇 |
1984年 | 2859篇 |
1983年 | 2301篇 |
1982年 | 2505篇 |
1981年 | 2402篇 |
1980年 | 2262篇 |
1979年 | 2491篇 |
1978年 | 2652篇 |
1977年 | 2452篇 |
1976年 | 2525篇 |
1975年 | 2380篇 |
1974年 | 2406篇 |
1973年 | 2460篇 |
1972年 | 1645篇 |
1971年 | 1451篇 |
1968年 | 1403篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.
The general structure of the pureSU(2) gauge potentials is calculated in detail. It is shown that the expansion of the gauge potentials about nonvanishing pure gauge potentials gives rise to new effects with confinement character. 相似文献
42.
43.
N. S. Simonović 《Few-Body Systems》2006,38(2-4):139-145
In agreement with the Kohn theorem the relative motion (rel) of three electrons in a two-dimensional parabolic trap separates
from the centre-of-mass (CM) motion. By introducing new coordinates the Hamiltonian for relative motion in the approximation
of non-interacting electrons can be taken to the normal form. The eigenstates of the normalized Hamiltonian are products of
the Fock-Darwin states for normal modes. The energy levels for relative motion are obtained by diagonalizing the exact Hamiltonian
in the eigenbasis for the non-interacting case. In this basis the interaction matrix elements can be obtained in the analytical
form. Since the rank of the Hamiltonian matrix is significantly reduced, the calculations are faster and more accurate than
those for the full (CM + rel) motion. This advantage is especially important for the calculations of excited states and the
analysis of energy spectra. 相似文献
44.
On Quantum Team Games 总被引:2,自引:0,他引:2
E. Ahmed M. F. Elettreby A. S. Hegazi 《International Journal of Theoretical Physics》2006,45(5):880-886
Recently Liu and Simaan (2004) convex static multi-team classical games have been introduced. Here they are generalized to both nonconvex, dynamic and quantum games. Puu's incomplete information dynamical systems are modified and applied to Cournot team game. The replicator dynamics of the quantum prisoner's dilemma game is also studied. 相似文献
45.
V. Edon M.C. Hugon B. Agius L. Miotti C. Radtke F. Tatsch J.J. Ganem I. Trimaille I.J.R. Baumvol 《Applied Physics A: Materials Science & Processing》2006,83(2):289-293
The influence of processing parameters on the electrical characteristics of RuO2/LaAlO3/Si metal-oxide-semiconductor structures was investigated. In particular, the sputtering regime during deposition of LaAlO3 on Si and the atmosphere used in the post-deposition annealing step were addressed by determining capacitance-voltage and
gate current-voltage characteristics. These results were correlated with compositional information obtained by Rutherford
backscattering spectrometry and nuclear reaction analysis. A post-deposition annealing step in oxygen at 600 °C resulted in
better electrical characteristics of the final structure as compared to the same treatment performed in nitrogen. This result
is explained by oxygen ability to heal oxygen vacancies in the LaAlO3 film, especially at the dielectric/semiconductor interface region. A thermalized sputtering regime during deposition of LaAlO3 on Si leads to capacitors with electrical characteristics superior to those deposited in ballistic regime.
PACS 77.84.Dy; 81.15.Cd; 81.40.Gh; 73.40.Qv; 82.80.Yc 相似文献
46.
F. Iachello S. Oss 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,19(3):307-314
We present a brief review of algebraic techniques developed and applied in molecular spectroscopy in the last five years.
We also outline perspectives for new applications of the Lie algebraic method in the first decade of the new century.
Received 21 November 2001 相似文献
47.
R. F. Bikbaev 《Journal of Mathematical Sciences》1991,57(3):3078-3083
Diffraction by a semitransparent screen is considered in the framework of the nonlinear Schrödinger equation. The case of a defocusing medium is investigated. The method used represents a synthesis of the method of Riemann's matrix problem and the technique of Whitham's deformations of spectral curves.Translated from Zapiski Nauchnykh Seminarov Leningradskogo Otdeleniya Matematicheskogo Instituta im. V. A. Steklova, Vol. 179, pp. 23–31, 1989. 相似文献
48.
Under idealized conditions, electroconvection in a nematic liquid crystal sets in at a well-defined threshold of the driving ac voltage. Fluctuating convection rolls of a small amplitude below that threshold have been observed recently. The measurement of the amplitude of these fluctuations is described in detail in this paper. It is based on averaging the light intensity signals using the structure function and a quantitative analysis of the light deflection. 相似文献
49.
Robert M. O'Keefe 《The Journal of the Operational Research Society》1989,40(5):415-422
Cognitive style refers to differences that can be perceived in individuals due to differing cognitive structures. There has been a large amount of research on how cognitive style affects managerial decision-making, particularly in the context of management information systems, but little or no attempt to relate these findings to operational research. This paper reviews the findings of cognitive-style research from the perspective of operational research, and draws a number of useful inferences concerning the matching of OR aids to managers, the presentation of information and recommendations, the use and acceptance of OR, and the structure of OR groups. Further, it is argued that cognitive-style findings help to give a justification to the move towards ‘soft’ approaches to analysis. 相似文献
50.