全文获取类型
收费全文 | 152928篇 |
免费 | 1358篇 |
国内免费 | 385篇 |
专业分类
化学 | 82128篇 |
晶体学 | 2030篇 |
力学 | 6670篇 |
综合类 | 7篇 |
数学 | 15312篇 |
物理学 | 48524篇 |
出版年
2020年 | 1120篇 |
2019年 | 1183篇 |
2018年 | 1495篇 |
2017年 | 1462篇 |
2016年 | 2487篇 |
2015年 | 1558篇 |
2014年 | 2440篇 |
2013年 | 6338篇 |
2012年 | 4943篇 |
2011年 | 6274篇 |
2010年 | 4293篇 |
2009年 | 4299篇 |
2008年 | 5702篇 |
2007年 | 5776篇 |
2006年 | 5408篇 |
2005年 | 4998篇 |
2004年 | 4411篇 |
2003年 | 3857篇 |
2002年 | 3884篇 |
2001年 | 4335篇 |
2000年 | 3316篇 |
1999年 | 2572篇 |
1998年 | 2242篇 |
1997年 | 2184篇 |
1996年 | 1981篇 |
1995年 | 1898篇 |
1994年 | 1886篇 |
1993年 | 1726篇 |
1992年 | 1991篇 |
1991年 | 2119篇 |
1990年 | 1917篇 |
1989年 | 1916篇 |
1988年 | 1856篇 |
1987年 | 1755篇 |
1986年 | 1692篇 |
1985年 | 2193篇 |
1984年 | 2324篇 |
1983年 | 1899篇 |
1982年 | 2079篇 |
1981年 | 1964篇 |
1980年 | 1888篇 |
1979年 | 2029篇 |
1978年 | 2197篇 |
1977年 | 2067篇 |
1976年 | 2112篇 |
1975年 | 2019篇 |
1974年 | 2072篇 |
1973年 | 2060篇 |
1972年 | 1354篇 |
1971年 | 1210篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
The European Physical Journal E - The isothermal gas adsorption of two hexane isomers (n-hexane and cyclohexane) in the mesopores of MCM-41 silica have been investigated by small angle neutron... 相似文献
2.
Ya. V. Fattakhov M. F. Galyautdinov T. N. L’vova I. B. Khaibullin 《Technical Physics》1997,42(12):1457-1459
The first results regarding the formation of a two-dimensional periodic structure of local melting regions on a silicon surface
upon pulsed light irradiation are presented. The conditions are established, and the mechanism of the formation of such structures
is discussed.
Zh. Tekh. Fiz. 67, 97–99 (December 1997) 相似文献
3.
4.
A. R. Volkov B. V. Shul'gin T. I. Polupanova V. N. Lebedev A. A. Nagornyi V. L. Petrov Yu. F. Kargin 《Journal of Applied Spectroscopy》1991,54(6):585-590
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 54, No. 6, pp. 970–975, June, 1991. 相似文献
5.
In a twisted nematic liquid crystal cell we report and study the self-transparency effect induced by the creation of an isotropic droplet. A simple theoretical model is presented and good agreement with experimental data is found. In a two beams configuration transistor-like behavior is observed and theoretically discussed. 相似文献
6.
Under idealized conditions, electroconvection in a nematic liquid crystal sets in at a well-defined threshold of the driving ac voltage. Fluctuating convection rolls of a small amplitude below that threshold have been observed recently. The measurement of the amplitude of these fluctuations is described in detail in this paper. It is based on averaging the light intensity signals using the structure function and a quantitative analysis of the light deflection. 相似文献
7.
William F. Bowlin 《The Journal of the Operational Research Society》1987,38(2):127-135
The objective of this research is to evaluate a new methodology, data envelopment analysis (DEA), as a tool for measuring and evaluating the operational efficiency of US Air Force organizations. This study involves the application of DEA to locate possible inefficiencies in the performance of US Air Force real-property maintenance activities. Dynamic behaviour, as exhibited via window analyses, is reviewed along with static counterparts. The testing was done in close coordination with Air Force officials, who reviewed the results for accuracy, validity and relevance. We conclude that this type of efficiency analysis does have value for the Air Force, where it can serve as a guide to auditors, budget programmers, managers and others in measuring, evaluating and enhancing operational efficiency. 相似文献
8.
J. Krause und F. Umland 《Fresenius' Journal of Analytical Chemistry》1989,335(7):791-795
Summary This paper presents some applications of cyclic voltammetry at the interface of two immiscible electrolyte solutions by means of an experimental set-up described in a former publication. When using special sample preparation good results are obtained for the determination of iodide and quinine in pharmaceutical products as well as for the determination of quinine in tonic water and dodecylsulfate in a tooth-salt.
Herrn Prof. Dr. Günther Tölg zum 60. Geburtstag gewidmet 相似文献
Herrn Prof. Dr. Günther Tölg zum 60. Geburtstag gewidmet 相似文献
9.
10.
V. Bradnova M. M. Chernyavsky L. Just S. P. Kharlamov A. D. Kovalenko M. Haiduc K. A. Kotel’nikov V. A. Krasnov V. G. Larionova F. G. Lepekhin A. I. Malakhov G. I. Orlova N. G. Peresadko N. G. Polukhina P. A. Rukoyatkin V. V. Rusakova N. A. Salmanova B. B. Simonov S. Vokal P. I. Zarubin 《Physics of Atomic Nuclei》2003,66(9):1646-1650
A physical program of irradiation of emulsions in beams of relativistic nuclei named the BECQUEREL Project is reviewed. It is destined to study in detail the processes of relativistic fragmentation of light radioactive and stable nuclei. The expected results would make it possible to answer some topical questions concerning the cluster structure of light nuclei. Owing to the best spatial resolution, the nuclear emulsions would enable one to obtain unique and evident results. The most important irradiations will be performed in the secondary beams of He, Be, B, C, and N radioactive nuclei formed on the basis of JINR Nuclotron beams of stable nuclei. We present results on the charged state topology of relativistic fragmentation of the 10B nucleus at low energy-momentum transfers as the first step of the research. 相似文献