全文获取类型
收费全文 | 1015篇 |
免费 | 148篇 |
国内免费 | 51篇 |
专业分类
化学 | 161篇 |
晶体学 | 5篇 |
力学 | 52篇 |
综合类 | 16篇 |
数学 | 426篇 |
物理学 | 554篇 |
出版年
2024年 | 2篇 |
2023年 | 16篇 |
2022年 | 19篇 |
2021年 | 22篇 |
2020年 | 30篇 |
2019年 | 22篇 |
2018年 | 27篇 |
2017年 | 37篇 |
2016年 | 30篇 |
2015年 | 28篇 |
2014年 | 35篇 |
2013年 | 84篇 |
2012年 | 39篇 |
2011年 | 46篇 |
2010年 | 47篇 |
2009年 | 44篇 |
2008年 | 58篇 |
2007年 | 57篇 |
2006年 | 71篇 |
2005年 | 51篇 |
2004年 | 57篇 |
2003年 | 42篇 |
2002年 | 54篇 |
2001年 | 36篇 |
2000年 | 33篇 |
1999年 | 33篇 |
1998年 | 26篇 |
1997年 | 24篇 |
1996年 | 12篇 |
1995年 | 11篇 |
1994年 | 13篇 |
1993年 | 13篇 |
1992年 | 7篇 |
1991年 | 7篇 |
1990年 | 13篇 |
1989年 | 7篇 |
1988年 | 6篇 |
1987年 | 4篇 |
1986年 | 6篇 |
1985年 | 5篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1982年 | 7篇 |
1981年 | 5篇 |
1980年 | 3篇 |
1979年 | 5篇 |
1978年 | 5篇 |
1976年 | 2篇 |
1972年 | 2篇 |
1971年 | 2篇 |
排序方式: 共有1214条查询结果,搜索用时 15 毫秒
91.
We investigate the effects of temperature and density on the single-particle and many-particle coefficients as well as on
the structures of homogenous systems in which the particles are assumed to interact via a continuous soft sphere potential
in the microcanonical ensemble. The pair distribution function and therefore the structures of the systems studied are affected
by temperature close to and above the melting point through migrations of atoms from the first shell in the pair distribution
function.
The dynamics of atomic pairs in the short-time regime in liquid aluminium may be said to be governed by the potential of mean
force, which depends on the static structure of liquid Al at all investigated temperatures. A polynomial dependence ofD on density and temperature was observed in contradiction to Arrhenius law. The shear viscosities of the systems studied are
largely nonlinear. It was observed that the soft sphere potential used in our calculations overestimates the Stoke-Einstein
relation. 相似文献
92.
In this work, the geometrical structures, the formation energies, and electronic states of the Na(ms)Arn polyatomic exciplexes with m = 3-6 and n = 2-5 are studied by using a quantum-classical method. The interaction potential between an electronically excited sodium atom and argon atoms are calculated by using a one-electron model involving electron-Ar and electron-Na+ pseudopotentials, in which the Hamiltonian is diagonalized at every optimization step in the Basin Hopping algorithm. The relationship between the position of the electronically excited levels and the cluster geometry is investigated as a function of the excitation level and of the spatial extension of the excited electron orbital. We show that the equilibrium structures of the ground state Na(3s)Arn and those of the electronically excited states Na(4s)Arn, Na(5s)Arn, and Na(6s)Arn are significantly different. As a result of the detailed examination of the relationships between the geometrical structure and density distribution of the Na valence electron of the Na∗Arn with n = 2-5 polyatomic exciplexes, we can see that for the Na(4s)Arn polyatomic exciplexes, the two extreme geometries, neutral Na(3s)Arn and ionic Na+Arn compete. It appears that none of them is the actual one. For Na(5s)Arn and Na(6s)Arn the valence electron is very weakly bound to the ionic core and described by a more diffused orbital so that the geometry and the formation energies of this excited state called Rydberg states converge towards those of the ionic cores. 相似文献
93.
94.
In this paper, we consider the three dimensional Cauchy problem of the compressible micropolar viscous flows. We prove the existence of unique global classical solution for smooth initial data with small initial energy but possibly large oscillations and the initial density may allowed to contain the interior and far field vacuum states. Furthermore, the large time behavior of the solution is obtained as well. 相似文献
95.
How Van der Waals Interactions Influence the Absorption Spectra of Pheophorbide a Complexes: A Mixed Quantum–Classical Study
下载免费PDF全文
![点击此处可从《Chemphyschem》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Dr. Jörg Megow 《Chemphyschem》2015,16(14):3101-3107
The computation of dispersive site energy shifts due to van der Waals interaction (London dispersion forces) was combined with mixed quantum–classical methodology to calculate the linear optical absorption spectra of large pheophorbide a (Pheo) dendrimers. The computed spectra agreed very well with the measurements considering three characteristic optical features occurring with increasing aggregate size: a strong line broadening, a redshift, and a low‐energy shoulder. The improved mixed quantum–classical methodology is considered a powerful tool in investigating molecular aggregates. 相似文献
96.
97.
Jesko Hüttenhain 《代数通讯》2017,45(9):3716-3723
We give a negative answer to a question by J. M. Landsberg on the nature of normalizations of orbit closures. A counterexample originates from the study of complex, ternary, cubic forms. 相似文献
98.
将一类双曲型方程混合问题转换成一阶抽象Cauchy问题,证明所得Hamilton算子矩阵H在相应空间中生成压缩半群,并借助Fourier变换,采用一致连续半群做逼近的方法,得到H所生成的压缩半群,进而给出了问题的古典解. 相似文献
99.
100.