全文获取类型
收费全文 | 1095篇 |
免费 | 392篇 |
国内免费 | 77篇 |
专业分类
化学 | 227篇 |
晶体学 | 12篇 |
力学 | 76篇 |
综合类 | 8篇 |
数学 | 36篇 |
物理学 | 1205篇 |
出版年
2024年 | 1篇 |
2023年 | 5篇 |
2022年 | 41篇 |
2021年 | 44篇 |
2020年 | 34篇 |
2019年 | 37篇 |
2018年 | 37篇 |
2017年 | 29篇 |
2016年 | 49篇 |
2015年 | 50篇 |
2014年 | 56篇 |
2013年 | 67篇 |
2012年 | 55篇 |
2011年 | 75篇 |
2010年 | 74篇 |
2009年 | 90篇 |
2008年 | 97篇 |
2007年 | 110篇 |
2006年 | 82篇 |
2005年 | 78篇 |
2004年 | 45篇 |
2003年 | 74篇 |
2002年 | 73篇 |
2001年 | 53篇 |
2000年 | 37篇 |
1999年 | 27篇 |
1998年 | 24篇 |
1997年 | 12篇 |
1996年 | 12篇 |
1995年 | 9篇 |
1994年 | 18篇 |
1993年 | 11篇 |
1992年 | 9篇 |
1991年 | 1篇 |
1990年 | 9篇 |
1989年 | 9篇 |
1988年 | 5篇 |
1987年 | 7篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1977年 | 1篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有1564条查询结果,搜索用时 578 毫秒
151.
介观RLC并联电路量子效应 总被引:1,自引:0,他引:1
研究了介观RLC并联电路系统量子态随时间的演化,结果表明,在外加电源作用下,有耗散的RLC并联电路,系统将由初始的真空态演化到压缩态。 相似文献
152.
C. Camerlingo H. Huang B. Ruggiero M. Russo E. Sarnelli G. Testa 《Il Nuovo Cimento D》1994,16(12):1967-1972
Summary Bicrystal grain boundary junctions of YBCO have been fabricated by using the Inverted Cylindrical Magnetron d.c. sputtering
technique. The main characteristics of the junction behaviour are reported. Some aspects of the experimental results are discussed
in the framework of existing models developed for describing weak-link structures.
Paper presented at the ?VII Congresso SATT?, Torino, 4–7 October 1994. 相似文献
153.
W.H. Wong C.F. Lo 《The European Physical Journal B - Condensed Matter and Complex Systems》1998,6(2):213-223
In the present work we have developed an optimal coupled-cluster approximation, which can take care of both the accuracies
of the ground-state energy and the wavefunction estimates, for the ground state of a two-state system coupled to a dispersionless
boson bath. This new approach is also able to give a tight upper bound to the ground-state energy of the system. Up to the
fourth level of this approximation our results show excellent agreement with the numerical exact diagonalization results.
In particular, our results suggest no discontinuous localization-delocalization transition of the two-state system. This is
consistent with the exact result.
Received: 11 March 1998 / Accepted: 23 June 1998 相似文献
154.
The I-V characteristics of a Josephson junction shunted by an Ohmic resistor shows sharp peaks when levels in neighbouring wells are crossing. We consider the shape and size of these peaks using a double-well model where the wells are given in parabolic approximation. The friction of arbitrary strength is included by the help of a bath of infinitely many degrees of freedom. 74.50.+z. 相似文献
155.
M. Wilkinson B. Mehlig 《The European Physical Journal B - Condensed Matter and Complex Systems》1998,1(4):397-398
We discuss the absorption of electromagnetic radiation in small conducting particles, in the case where the electron motion
is diffusive. We refine an earlier theory in which we calculated the absorption coefficient using an effective potential describing
the screened electric field. Our new theory incorporates the effects of non-locality in the electrical conductivity, and shows
how the two limiting behaviours of the effective potential at high and low frequencies can be derived from a unified theory.
Our results are in full agreement with our earlier calculation.
Received: 3 November 1997 / Accepted: 29 January 1998 相似文献
156.
Summary In an important experiment performed on a SQUID system, Rouse, Han and Lukens report the first observation of resonant tunnelling
between macroscopically distinct quantum levels. We support the experiment with the first theoretical approach for the phenomenon. 相似文献
157.
G. Tonini F. Werner Y. Castin 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2006,39(2):283-294
We investigate theoretically the formation of a vortex lattice in
a superfluid two-spin component Fermi gas in a rotating harmonic trap, in a BCS-type
regime of condensed non-bosonic pairs.
Our analytical solution of the superfluid
hydrodynamic equations, both for the 2D BCS equation of state
and for the 3D unitary quantum gas, predicts that the vortex free gas is
subject to a dynamic instability for fast enough rotation.
With a numerical solution of the full
time dependent BCS equations in a 2D model, we confirm the existence of this dynamic
instability and we show that it leads to the formation of a regular pattern
of quantum vortices in the gas. 相似文献
158.
K. P. Schmidt A. Reischl G. S. Uhrig 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2006,38(2):343-352
In this work we give a consistent picture of the thermodynamic properties of
bosons in the Mott insulating phase when loaded adiabatically into
one-dimensional optical lattices. We find a crucial dependence of the
temperature in the optical lattice on the doping level of the Mott
insulator. In the undoped case, the temperature is of the order of the large
onsite
Hubbard interaction. In contrast, at a finite doping level the
temperature jumps almost immediately to the order of the small hopping
parameter. These two situations are investigated on the one hand by considering
limiting cases like the atomic limit and the case of free fermions. On the
other hand, they are examined using a quasi-particle conserving continuous
unitary transformation extended by an approximate thermodynamics for
hardcore particles. 相似文献
159.
E. Lundh 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,46(3):517-520
Two effects are identified that affect the visibility of the
Mott transition in an atomic gas in an optical lattice confined
in a power-law potential. The transition can be made more
pronounced by increasing the power law, but at the same time,
experimental uncertainty in the number of particles will
induce corresponding fluctuations in the measured condensate
fraction. Calculations in two dimensions
indicate that a potential slightly more flat-bottomed than a
quadratic one is to be preferred for a wide range of
particle number fluctuation size. 相似文献
160.
Critical comparisons are drawn between the basic electrical properties of semiconductor/metal, semiconductor/liquid, and semiconductor/conducting polymer junctions. A theoretical model is developed to describe the basic current-voltage properties of semiconductor contacts, with emphasis on the contrasts between ideal and observed behavior. Using the concepts from this model, the characteristics of a variety of semiconductor contacts are evaluated. The discussion focuses on the following semiconductors: Si, GaAs, InP, and II-VI compounds based on the Cd-(chalcogenide) materials. 相似文献