全文获取类型
收费全文 | 4203篇 |
免费 | 26篇 |
国内免费 | 8篇 |
学科分类
工业技术 | 4237篇 |
出版年
2022年 | 47篇 |
2021年 | 70篇 |
2020年 | 44篇 |
2019年 | 50篇 |
2018年 | 126篇 |
2017年 | 135篇 |
2016年 | 169篇 |
2015年 | 62篇 |
2014年 | 100篇 |
2013年 | 147篇 |
2012年 | 144篇 |
2011年 | 162篇 |
2010年 | 131篇 |
2009年 | 158篇 |
2008年 | 148篇 |
2007年 | 140篇 |
2006年 | 105篇 |
2005年 | 99篇 |
2004年 | 77篇 |
2003年 | 79篇 |
2002年 | 82篇 |
2001年 | 69篇 |
2000年 | 72篇 |
1999年 | 70篇 |
1998年 | 94篇 |
1997年 | 74篇 |
1996年 | 67篇 |
1995年 | 73篇 |
1994年 | 47篇 |
1993年 | 59篇 |
1992年 | 42篇 |
1991年 | 51篇 |
1990年 | 50篇 |
1989年 | 47篇 |
1986年 | 45篇 |
1984年 | 44篇 |
1983年 | 52篇 |
1982年 | 48篇 |
1981年 | 55篇 |
1980年 | 44篇 |
1979年 | 47篇 |
1978年 | 74篇 |
1977年 | 65篇 |
1976年 | 81篇 |
1975年 | 52篇 |
1974年 | 52篇 |
1973年 | 48篇 |
1972年 | 44篇 |
1971年 | 40篇 |
1968年 | 37篇 |
排序方式: 共有4237条查询结果,搜索用时 0 毫秒
41.
The structure and phase composition of the samples of foam aluminum based on the AMg6 alloy (Al-6%Mg-0.7%Mn) obtained in a high-energy planetary mill are investigated. Mechanical doping provides high dispersity and homogeneity of all structural components including particles of the foam agent TiH2, which allows one to obtain foam aluminum with a pore size of 1–5 mm at a density of 1.20–0.80 g/cm3. Mechanical properties of foam aluminum were estimated based on the results of compression tests. Based on preliminary investigations, an imitation model of foam formation is suggested that well describes the process of foam formation. 相似文献
42.
A method of processing complex signals in passive multi-element antenna arrays based on an analysis of the natural values of the correlation matrix of the signal is considered. By means of the method it is possible to substantially increase the output signal-to-noise ratio. An iterational process by means of which optimal estimators of both the signal and the amplitude-phase distribution may be obtained, is proposed. Theoretical estimators of the efficiency of the method are given. It is proved that, in terms of the efficiency, the approach considered in the article comes close to the technique of matched filtration. Results of statistical modeling that confirm the statistical results are presented. 相似文献
43.
44.
V. N. Shevchenko N. M. Ivanov Yu. A. Zvezdina 《Optoelectronics, Instrumentation and Data Processing》2007,43(1):1-6
A non-quadratic regularization algorithm modification is proposed. It ensures identifying and filtering angular spectrum false components by choosing regularizing functional parameters. The algorithm efficiency was proved by modeling while solving the problem of multibeam wavefield division using one input data realization. 相似文献
45.
A. S. Gouralnik N. G. Galkin V. A. Ivanov M. V. Ivanchenko E. A. Chusovitin 《Instruments and Experimental Techniques》2007,50(3):408-410
The design of a simple pulse-type evaporator ensuring a high rate (up to ~104 nm/s) of deposition of thin films (0.01–100 nm thick) onto a solid surface in ultrahigh vacuum is described. The evaporation pulse is created by discharge of a capacitor bank via a fast-response evaporator produced from a tungsten foil. Results illustrating the efficiency of this device are presented. 相似文献
46.
47.
A. V. Ivanov 《Power Technology and Engineering (formerly Hydrotechnical Construction)》2007,41(6):327-331
Successful introduction of pisciculture to reservoirs by the method of migratory fish-farm pasturing is described.
__________
Translated from Gidrotekhnicheskoe Stroitel’stvo, No. 9, September 2007, pp. 36–40. 相似文献
48.
49.
All-Russia Scientific-Research Institute of Electrophysical Apparatus. Special Office of Machine Design. Institute of High
Temperatures, Russian Academy of Sciences. Translated from Atomnaya énergiya, Vol. 79, No. 3, pp. 178–188, September, 1995. 相似文献
50.
S. M. Popov V. V. Voloshin I. L. Vorobyov G. A. Ivanov A. O. Kolosovskii V. A. Isaev Y. K. Chamorovskii 《Optical Memory & Neural Networks》2012,21(1):45-51
Temperature band of ordinary telecommunication optical fibers is −60...85°C. The developing fiber optic sensors which can
work at higher temperatures, required to develop metal coated optical fibers. The Purpose of the work is a researching additional
optical loss of copper alloy coated optical fibers which were drawn from low hydroxyl group contamination preforms at temperatures
20...800°C. It is reached that metal coated optical fiber worked at temperature 700°C for 7 hours, while the optical losses
changed from 2 to 3 dB/km at the wavelength of λ = 1300 nm. It is not observed intensive growth of optical losses on hydroxyl
groups at 800°C, which was observed in metal coated optical fiber when it was heated at 700°C. 相似文献