全文获取类型
收费全文 | 424082篇 |
免费 | 3178篇 |
国内免费 | 1018篇 |
专业分类
化学 | 220757篇 |
晶体学 | 6805篇 |
力学 | 20673篇 |
综合类 | 18篇 |
数学 | 49067篇 |
物理学 | 130958篇 |
出版年
2020年 | 3600篇 |
2019年 | 4245篇 |
2018年 | 5918篇 |
2017年 | 5946篇 |
2016年 | 8260篇 |
2015年 | 4536篇 |
2014年 | 7675篇 |
2013年 | 17595篇 |
2012年 | 13399篇 |
2011年 | 16178篇 |
2010年 | 12083篇 |
2009年 | 12025篇 |
2008年 | 15182篇 |
2007年 | 15316篇 |
2006年 | 13928篇 |
2005年 | 12491篇 |
2004年 | 11674篇 |
2003年 | 10606篇 |
2002年 | 10504篇 |
2001年 | 11581篇 |
2000年 | 8847篇 |
1999年 | 6831篇 |
1998年 | 5944篇 |
1997年 | 6023篇 |
1996年 | 5557篇 |
1995年 | 5074篇 |
1994年 | 5277篇 |
1993年 | 4959篇 |
1992年 | 5651篇 |
1991年 | 5694篇 |
1990年 | 5558篇 |
1989年 | 5474篇 |
1988年 | 5499篇 |
1987年 | 5383篇 |
1986年 | 5135篇 |
1985年 | 6716篇 |
1984年 | 7057篇 |
1983年 | 5880篇 |
1982年 | 5949篇 |
1981年 | 5876篇 |
1980年 | 5660篇 |
1979年 | 5936篇 |
1978年 | 6231篇 |
1977年 | 6291篇 |
1976年 | 6315篇 |
1975年 | 5863篇 |
1974年 | 5872篇 |
1973年 | 6117篇 |
1972年 | 4424篇 |
1971年 | 3860篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
81.
A.N Bekrenev 《Journal of Physics and Chemistry of Solids》2002,63(9):1627-1631
An unusually high mobility of atoms under intensive impulse reactions is explained by the behavior of point defects at the shock wave front. It is shown that either a shock wave front or moving dislocations can capture the interstitials, or they can be thermally activated in the direction of the shock wave propagation. 相似文献
82.
83.
A. I. Bril' V. P. Kabashnikov N. V. Kuz'mina Yu. V. Khodyko 《Journal of Applied Spectroscopy》1991,55(3):934-939
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 55, No. 3, pp. 478–484, September, 1991. 相似文献
84.
A fast-frequency modulated (FM) diode laser has been optically narrowed using the technique of resonant optical feedback, to provide linewidths in each FM mode of ≈ 200 kHz peak-to-peak. With a drive frequency of 50 MHz and modulation index of 0.2, the FM laser has been used for the first time to obtain Doppler-free FM spectra of the Rb D1 line at 795 nm. The potential use of this system for laser frequency stabilisation is discussed. 相似文献
85.
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
86.
Large fault-tolerant interconnection networks 总被引:5,自引:0,他引:5
This paper deals with reliability and fault-tolerant properties of networks. We first survey general reliability properties of networks, in particular those concerning diameter vulnerability. Then we study in details reliability properties of some families of networks in particular de Bruijn and Kautz networks and their generalizations which appear as very good fault-tolerant networks. 相似文献
87.
88.
89.
90.
Photoisomerization of provitamin D 3 (7-dehydrocholesterol) in a nematic liquid crystal (ZLI-1695, Merck) is investigated in detail by UV absorption spectroscopy. It is found that dissolution of chiral molecules of provitamin D 3 induces the cholesteric phase in a nematic. The spectral kinetics of photoisomerization in this phase changes significantly from that in an ethanol solution. A sharp nonmonotonic dependence of the increase in accumulation of trans isomer tachysterol in a liquid crystal matrix with a decrease in the induced cholesteric pitch from 2200 to 25 μm is revealed. 相似文献