全文获取类型
收费全文 | 893篇 |
免费 | 18篇 |
国内免费 | 4篇 |
专业分类
化学 | 611篇 |
晶体学 | 13篇 |
力学 | 5篇 |
数学 | 47篇 |
物理学 | 239篇 |
出版年
2021年 | 5篇 |
2020年 | 5篇 |
2019年 | 6篇 |
2018年 | 13篇 |
2017年 | 7篇 |
2016年 | 17篇 |
2015年 | 15篇 |
2014年 | 7篇 |
2013年 | 45篇 |
2012年 | 32篇 |
2011年 | 29篇 |
2010年 | 17篇 |
2009年 | 32篇 |
2008年 | 56篇 |
2007年 | 32篇 |
2006年 | 44篇 |
2005年 | 37篇 |
2004年 | 35篇 |
2003年 | 36篇 |
2002年 | 44篇 |
2001年 | 20篇 |
2000年 | 32篇 |
1999年 | 14篇 |
1998年 | 6篇 |
1997年 | 11篇 |
1996年 | 21篇 |
1995年 | 13篇 |
1994年 | 7篇 |
1993年 | 20篇 |
1992年 | 9篇 |
1991年 | 7篇 |
1990年 | 17篇 |
1989年 | 11篇 |
1988年 | 19篇 |
1987年 | 16篇 |
1986年 | 14篇 |
1985年 | 22篇 |
1984年 | 18篇 |
1983年 | 11篇 |
1982年 | 8篇 |
1981年 | 12篇 |
1980年 | 5篇 |
1979年 | 9篇 |
1978年 | 9篇 |
1977年 | 13篇 |
1976年 | 10篇 |
1975年 | 13篇 |
1973年 | 3篇 |
1972年 | 5篇 |
1936年 | 3篇 |
排序方式: 共有915条查询结果,搜索用时 187 毫秒
111.
A thermoplastic photoconductor material is well-known as a hologram recording material. The dynamic ranges of a thermoplastic hologram are studied in two softening methods. One is the conventional heating method, and the other is the newly developed solvent vapor method. It is found that the solvent vapor method makes the dynamic range ten times as wide as the heating method, and in the solvent vapor method exposure time and charging voltage hardly affect the final diffraction efficiency. 相似文献
112.
Determination of Th and U at ppt levels in a neutral hot spring water by neutron activation analysis
Y. Kikawada T. Honda T. Oi T. Ossaka H. Kakihana 《Journal of Radioanalytical and Nuclear Chemistry》1991,153(5):357-364
Neutron activation analysis was successfully applied to the determination of Th and U at ppt levels in a neutral hot spring water. Blank test corrections were found to be essential to reach the final determined values. Normal NAA is a better method for the Th determination than epithermal NAA, while both NAAs are nearly equally effective for U determination. 相似文献
113.
114.
115.
116.
A new method for holographic recording on a thermoplastic-photoconductor has been developed. By using this new method which involves the application of white light to the thermoplastic-photoconductor after exposure, the sensitivity, reciprocity and signal-to-noise ratio have been improved. A higher diffraction efficiency (about 30%) can also be obtained. 相似文献
117.
[reaction: see text] A novel and efficient synthetic method is described for (2S,3S)-3-amino-2-hydroxy-4-phenyl butyric acid derivatives, which are useful intermediates of enzyme inhibitors. This involves a Pummerer rearrangement of a beta-ketosulfoxide derived from l-phenylalanine followed by highly stereoselective acyl migration. From these studies, it appears that nitrogen-protecting groups exert a substantial influence over stereoselectivity. The mechanism of the rearrangement is discussed. beta-Amino alpha-hydroxy carboxylic acids are important pharmaceutical intermediates, and this method may provide a versatile synthesis from various amino acids in a few steps. 相似文献
118.
119.
Summary CuGaS2 crystals grown by iodine transport exhibit room temperature photoluminescences at 2.45 eV and at 1.44 eV. The spectral distribution
of the green emission is shown to be relatively well described by the calculated curve for a direct band-to-band transition
withk-selection. The heterojunction formation has been tried between sulfur-treated CuGaS2 crystals and low-resistivity amorphous ZnS films prepared by sputtering at room temperature. TheI–V characteristic of the diode shows rectifying behaviour, but no injection luminescence has been observed.
Paper presented at the ?V International Conference on Ternary and Multinary Compounds?, held in Cagliari, September 14–16,
1982. 相似文献
120.
Double-exposure holographic interferometry is applied to measure the elastic deformation of rotating objects. The first exposure is made in the rotating state and the second in the static state. The precise positioning of the object between the two exposures is obtained by using holographically produced Haidinger's fringes. 相似文献