全文获取类型
收费全文 | 1191篇 |
免费 | 80篇 |
国内免费 | 64篇 |
专业分类
化学 | 427篇 |
晶体学 | 2篇 |
力学 | 56篇 |
综合类 | 3篇 |
数学 | 382篇 |
物理学 | 465篇 |
出版年
2023年 | 16篇 |
2022年 | 10篇 |
2021年 | 30篇 |
2020年 | 33篇 |
2019年 | 29篇 |
2018年 | 40篇 |
2017年 | 25篇 |
2016年 | 23篇 |
2015年 | 36篇 |
2014年 | 40篇 |
2013年 | 110篇 |
2012年 | 46篇 |
2011年 | 42篇 |
2010年 | 33篇 |
2009年 | 63篇 |
2008年 | 85篇 |
2007年 | 82篇 |
2006年 | 65篇 |
2005年 | 45篇 |
2004年 | 48篇 |
2003年 | 51篇 |
2002年 | 50篇 |
2001年 | 34篇 |
2000年 | 43篇 |
1999年 | 37篇 |
1998年 | 28篇 |
1997年 | 26篇 |
1996年 | 16篇 |
1995年 | 11篇 |
1994年 | 16篇 |
1993年 | 8篇 |
1992年 | 17篇 |
1991年 | 5篇 |
1990年 | 11篇 |
1989年 | 8篇 |
1988年 | 7篇 |
1987年 | 8篇 |
1986年 | 5篇 |
1985年 | 7篇 |
1984年 | 9篇 |
1982年 | 7篇 |
1981年 | 5篇 |
1980年 | 6篇 |
1979年 | 2篇 |
1978年 | 5篇 |
1977年 | 3篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1974年 | 3篇 |
1973年 | 3篇 |
排序方式: 共有1335条查询结果,搜索用时 31 毫秒
141.
Andréi Zaitsevskii Elena Rykova Nikolai S. Mosyagin Anatoly V. Titov 《Central European Journal of Physics》2006,4(4):448-460
The relativistic effective core potential (RECP) approach combined with the spin-orbit DFT electron correlation treatment
was applied to the study of the bonding of eka-mercury (E112) and mercury with hydrogen and gold atoms. Highly accurate small-core
shape-consistent RECPs derived from Hartree-Fock-Dirac-Breit atomic calculations with Fermi nuclear model were employed. The
accuracy of the DFT correlation treatment was checked by comparing the results in the scalar-relativistic (spin-orbit-free)
limit with those of high level scalar-relativistic correlation calculations within the same RECP model. E112H was predicted
to be slightly more stable than its lighter homologue (HgH). The E112-Au bond energy is expected to be ca. 25–30 % weaker
than that of Hg-Au. The role of correlations and magnetic (spin-dependent) interactions in E112-X and Hg-X (X=H, Au) bonding
is discussed. The present computational procedure can be readily applied to much larger systems and seems to be a promising
tool for simulating E112 adsorption on metal surfaces. 相似文献
142.
分子拓扑学方法估算多环芳香烃类化合物的电离能 总被引:2,自引:0,他引:2
在构建多环芳烃类化合物分子的邻接矩阵主对角元时,结合烷基极化效应指数考虑分子图顶点的性质,以分子碎片C、CH、CH2、CH3等的相对能量作主元,用分子拓扑学方法构建了多环芳香烃类化合物新的邻接矩阵.研究结果发现,新的邻接矩阵特征根与多环芳香烃类化合物的电离能有良好的相关性Ipi=4.756+2.870OMOi,R=0.9853,s=0.1765,n=446.用这种新方法估算多环芳香烃类化合物的电离能,所用参数少且为分子结构性参数,稳定可靠,计算简便,结果较满意. 相似文献
143.
A. E. Kramida M.-C. Buchet-Poulizac 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2006,39(2):173-188
All experimental data on the
valence-shell-excited and core-excited spectra of Li-like neon, including
previously unpublished beam-foil spectroscopy data, have been compiled and
critically evaluated. Seventeen spectral lines have been newly identified.
Sets of recommended energy levels have been derived from the total list of
observed lines and from selected results of theoretical and semi-empirical
calculations. An accurate value of the ionization potential has been derived
from existing theoretical calculations.
Electronic supplementary material Online Material 相似文献
144.
In this paper,we present a general Mobius inversion transform formula for hcp lattices.This formula can be applied to hcp lattices with a non-ideal c/a value and to obtain the pair potential between atoms in these lattices from the cohesive energy.Also,the three-body interaction among atoms in the lattices can be taken into account in the method.This method gives a useful means to obtain interatomic interactions in the interatomic force model.The method has been applied to zinc,and the pair potential obtained is used to calculate the phonon dispersion relations for some high-symmetry directions.It is found that,by properly considering a three-body interaction,one can acquire satisfactory results. 相似文献
145.
The Schrödinger equation with a time-dependent quadratic plus quartic Hamiltonian is considered. A rigorous Feynman path integral representation for its solution is given in terms of a well-defined infinite-dimensional oscillatory integral. 相似文献
146.
A systematic and intuitive approach for the separation of variables of the three-dimensional Dirac equation in spherical coordinates is presented. Using this approach, we consider coupling of the Dirac spinor to electromagnetic four-vector potential that satisfies the Lorentz gauge. The space components of the potential have angular (non-central) dependence such that the Dirac equation becomes separable in all coordinates. We obtain exact solutions for a class of three-parameter static electromagnetic potential whose time component is the Coulomb potential. The relativistic energy spectrum and corresponding spinor wave functions are obtained. The Aharonov–Bohm and magnetic monopole potentials are included in these solutions. 相似文献
147.
148.
硝基甲苯类炸药C-NO2键中点的静电势 总被引:3,自引:2,他引:1
利用HONDO程序包,采用从头计算法对硝基甲苯类炸药的分子结构及其C-NO2键中点的静电势进行了计算,讨论了硝基甲苯类炸药C-NO2键中点的静电势最大值Vmidmax与其实验撞击感度之间的关系.研究表明:对于硝基甲苯类炸药,可用其分子C-NO2键中点的静电势最大值Vmidmax来确定其撞击感度的变化趋势.以静电势为判据,讨论了硝基和甲基数目以及硝基和甲基的相对位置对这类炸药撞击感度的影响. 相似文献
149.
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
150.
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