全文获取类型
收费全文 | 26900篇 |
免费 | 5730篇 |
国内免费 | 4499篇 |
专业分类
化学 | 16611篇 |
晶体学 | 668篇 |
力学 | 2369篇 |
综合类 | 294篇 |
数学 | 1571篇 |
物理学 | 15616篇 |
出版年
2024年 | 79篇 |
2023年 | 298篇 |
2022年 | 708篇 |
2021年 | 956篇 |
2020年 | 1152篇 |
2019年 | 943篇 |
2018年 | 957篇 |
2017年 | 1195篇 |
2016年 | 1397篇 |
2015年 | 1233篇 |
2014年 | 1666篇 |
2013年 | 2541篇 |
2012年 | 1885篇 |
2011年 | 1903篇 |
2010年 | 1625篇 |
2009年 | 1785篇 |
2008年 | 1738篇 |
2007年 | 1830篇 |
2006年 | 1712篇 |
2005年 | 1414篇 |
2004年 | 1293篇 |
2003年 | 1178篇 |
2002年 | 965篇 |
2001年 | 840篇 |
2000年 | 821篇 |
1999年 | 755篇 |
1998年 | 632篇 |
1997年 | 512篇 |
1996年 | 440篇 |
1995年 | 384篇 |
1994年 | 327篇 |
1993年 | 300篇 |
1992年 | 253篇 |
1991年 | 204篇 |
1990年 | 159篇 |
1989年 | 148篇 |
1988年 | 160篇 |
1987年 | 114篇 |
1986年 | 100篇 |
1985年 | 80篇 |
1984年 | 60篇 |
1983年 | 33篇 |
1982年 | 65篇 |
1981年 | 56篇 |
1980年 | 44篇 |
1979年 | 52篇 |
1978年 | 27篇 |
1977年 | 30篇 |
1976年 | 19篇 |
1974年 | 17篇 |
排序方式: 共有10000条查询结果,搜索用时 390 毫秒
111.
LUO You-Hua GE Zi-Ming 《理论物理通讯》2006,46(12)
In noncommutative space, we examine the problem of a noninteracting and harmonically trapped BoseEinstein condensate, and derive a simple analytic expression for the effect of spatial noncommutativity on energy spectrum of the condensate. It indicates that the ground-state energy incorporating the spatial noncommutativity is reduced to a lower level, which depends upon the noncommutativity parameter θ. The gap between the noncommutative space and commutative one for the ground-state level of the condensate should be a signal of spatial noncommutativity. 相似文献
112.
在e-A深度非弹性散射过程中, 喷注穿过冷核介质时, 多重散射诱导胶子辐射会导致对碎裂函数的修正及喷注的能量损失.前期研究中关于计算e-A深度非弹性散射中胶子辐射振幅的两种方法: 螺旋振幅近似和微扰QCD严格计算都异常繁杂.
本文发展了一种新的方法, 可以方便计算出多重散射导致胶子辐射的振幅, 得到的碎裂函数的修正以及能量损失与严格计算的结果一致. 相似文献
113.
Ryohei Tsuda Sayaka Kaino Hisashi Kokubo Shin-Ichiro Imabayashi Masayoshi Watanabe 《Colloids and surfaces. B, Biointerfaces》2007,56(1-2):255-Optics
Redox properties of phenothiazine-labeled poly(ethyl glycidy ether)-block-poly(ethylene oxide) (PT-EGEn-b-EOm) are reversibly changed by core-shell micelle formation. In the temperature range higher than the critical micellization temperature (cmt), the anodic potential of PT group positively shifts and concomitantly its anodic current decrease, or levels off compared to those of the reference polymer PT-EOm without the thermo-responsive EGEn segment. The former alteration is caused by incorporation of hydrophobic PT groups into a core of the micelle and the latter by the decrease in the diffusion coefficient of PT groups due to formation of the core-shell micelles. The cmt value and the temperature-dependent alteration in the redox properties strongly depend on the polymer structure, especially the length of thermo-responsive EGEn segment. The electrochemically determined hydrodynamic radii of the polymer aggregates seem to be overestimated, compared to the values reported for the aggregates of other thermo-responsive polymers with similar molecular weights, implying the presence of electrochemically inactive PT groups in the copolymers having longer thermo-responsive segments. 相似文献
114.
Kwang-Hua W. Chu 《International Journal of Theoretical Physics》2007,46(12):3230-3233
The modified Gross–Pitaevskii equation was derived and solved to obtain the 1D solution in the zero-energy limit. This stationary
solution could account for the dominated contributions due to the kinetic effect as well as the chemical potential in inhomogeneous
Bose gases. 相似文献
115.
116.
I. A. Anoshko V. S. Ermachenko L. E. Sandrigailo 《Journal of Applied Spectroscopy》2007,74(1):102-106
We present the results of a spectroscopic study of a nonequilibrium plasma in a Hall accelerator, in particular for such an
important parameter as the electron temperature. For the studied conditions, we used the semicoronal equilibrium model, which
relates the intensity ratios for two successive ionization steps for the same element.
__________
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 74, No. 1, pp. 93–96, January–February, 2007. 相似文献
117.
118.
Tensile impact experiments of EC8.0−24×7 glass fiber bundles at different low temperaturesT(14°C, −40°C and −10°C) and strain rates ɛ were carried out, and complete stress-strain curves were obtained. Within the range
of the experiment temperatures and strain rates, it is found that the initial modulusE, the ultimate strength σmax and the unstable strain ɛ
b
of the glass fiber bundles all increase with ɛ at an identicalT. At an identical ɛ, with the decrease ofT, E and σmax increase; but ɛ
b
increases when 10°C>T>−40°C and decreases when −40°C>T>−100°C. The strain-rate- and temperature-dependent bimodal Weibull statistical constitutive theory was adopted for the statistical
analysis of the experimental results, and the Weibull parameters of single fiber were obtained. The results show that the
bimodal Weibull distribution function is suitable to represent the strength distribution of the glass fiber at low temperature
and different strain rates. The differences in the mechanical properties between EC8.0−24×7 and EC5.5−12 ×14 glass fiber bundles
were also discussed.
Project supported by the National Natural Science Foundation of China (No. 19772058). 相似文献
119.
F.Oner R.A.Mamedoy 《理论物理通讯》2002,37(3):327-330
Behavior of the Coulomb energy difference for light nuclei is explained in terms of the different values of the average Coulomb interaction between two particles.Coulomb energy difference according to shell model of light mirror nuclei in the Coulomb and exchange integrals in the formula can be explained with exponential-type wavefunctions.In this study,using the one-center expansion of exponential-type wavefunctions in terms of Slater-type orbitals with the same center,we derived formula for Coulomb energy difference of light mirror nuclei. 相似文献
120.
用密耦近似方法计算了He和N2体系的微分截面和总截面及转动激发分波截面,得出微分截面及总截面随入射能量变化的规律. 相似文献