全文获取类型
收费全文 | 2441篇 |
免费 | 151篇 |
国内免费 | 45篇 |
专业分类
化学 | 1616篇 |
晶体学 | 12篇 |
力学 | 73篇 |
数学 | 237篇 |
物理学 | 523篇 |
综合类 | 176篇 |
出版年
2024年 | 7篇 |
2023年 | 22篇 |
2022年 | 52篇 |
2021年 | 89篇 |
2020年 | 84篇 |
2019年 | 121篇 |
2018年 | 122篇 |
2017年 | 94篇 |
2016年 | 146篇 |
2015年 | 98篇 |
2014年 | 107篇 |
2013年 | 166篇 |
2012年 | 153篇 |
2011年 | 191篇 |
2010年 | 113篇 |
2009年 | 107篇 |
2008年 | 130篇 |
2007年 | 126篇 |
2006年 | 123篇 |
2005年 | 97篇 |
2004年 | 76篇 |
2003年 | 62篇 |
2002年 | 56篇 |
2001年 | 33篇 |
2000年 | 27篇 |
1999年 | 34篇 |
1998年 | 15篇 |
1997年 | 17篇 |
1996年 | 24篇 |
1995年 | 23篇 |
1994年 | 15篇 |
1993年 | 24篇 |
1992年 | 12篇 |
1991年 | 9篇 |
1990年 | 17篇 |
1989年 | 5篇 |
1988年 | 4篇 |
1987年 | 2篇 |
1986年 | 4篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1982年 | 6篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1976年 | 6篇 |
1974年 | 2篇 |
1971年 | 2篇 |
1969年 | 1篇 |
排序方式: 共有2637条查询结果,搜索用时 296 毫秒
1.
2.
3.
4.
5.
Baochun Guo Xing Ouyang Changgeng Cai Demin Jia 《Journal of Polymer Science.Polymer Physics》2004,42(7):1192-1198
Montmorillonite (MMT) was modified with the acidified cocamidopropyl betaine (CAB) and the resulting organo‐montmorillonite (O‐MMT) was dispersed in an epoxy/methyl tetrahydrophthalic anhydride system to form epoxy nanocomposites. The intercalation and exfoliation behavior of the epoxy nanocomposites were examined by X‐ray diffraction and transmission electron microscopy. The curing behavior and thermal property were investigated by in situ Fourier transform infrared spectroscopy and DSC, respectively. The results showed that MMT could be highly intercalated by acidified CAB, and O‐MMT could be easily dispersed in epoxy resin to form intercalated/exfoliated epoxy nanocomposites. When the O‐MMT loading was lower than 8 phr (relative to 100 phr resin), exfoliated nanocomposites were achieved. The glass‐transition temperatures (Tg's) of the exfoliated nanocomposite were 20 °C higher than that of the neat resin. At higher O‐MMT loading, partial exfoliation was achieved, and those samples possessed moderately higher Tg's as compared with the neat resin. O‐MMT showed an obviously catalytic nature toward the curing of epoxy resin. The curing rate of the epoxy compound increased with O‐MMT loading. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 1192–1198, 2004 相似文献
6.
提出利用标定平面的两个角度可交出转台轴线,通过交出的轴线,标定出光-象平面轴线的关系,并给出测量点通过平移、旋转再进入标定矩阵的一个新的转换矩阵。 相似文献
7.
For the first time a comparative study of holographic recording in planarly oriented films of nematic and cholesteric azobenzene-containing polymers was performed. The influence of temperature and light intensity on the values of diffraction efficiencies of holographic gratings was investigated. The kinetics of grating relaxation at different temperatures was studied. It was shown that the helical supramolecular structure of cholesteric copolymer causes a significant decrease of the diffraction efficiency in comparison with the one observed for the nematic state of the homopolymer. 相似文献
8.
Alexey Yurasov Alexander Granovsky Sergey Tarapov Jean-Pierre Clerc 《Journal of magnetism and magnetic materials》2006
The transmission of millimeter-range electromagnetic waves (30–50 GHz) through a magnetic nanocomposite thin film exhibiting tunnel magnetoresistance (TMR) is calculated. The relative change of transmission coefficient in an applied magnetic field due to the magnetorefractive effect is approximately linear with TMR and strongly depends on nanocomposite resistivity and film thickness. The obtained results are in a good agreement with experiment. 相似文献
9.
介绍了具有位置反馈信息旋转平台的图象数据采集方法,以及对采集到的图象进行智能化快速细化的新方法,使得在一周内的36幅图象做到边采集边细化,而且仅用40s时间。 相似文献
10.
V. A. Demin 《Fluid Dynamics》2008,43(4):524-532
The free oscillations of a capillary bridge whose equilibrium shape is determined by the surface tension forces and the static gravity field are investigated. The values of 25 “lower” levels of the spectrum of natural oscillations of the capillary bridge are found for various control parameters in accordance with the experimental conditions. 相似文献