全文获取类型
收费全文 | 206101篇 |
免费 | 2208篇 |
国内免费 | 565篇 |
专业分类
电工技术 | 3510篇 |
综合类 | 141篇 |
化学工业 | 31821篇 |
金属工艺 | 10265篇 |
机械仪表 | 7010篇 |
建筑科学 | 3995篇 |
矿业工程 | 2161篇 |
能源动力 | 4631篇 |
轻工业 | 12876篇 |
水利工程 | 2920篇 |
石油天然气 | 7726篇 |
武器工业 | 22篇 |
无线电 | 21498篇 |
一般工业技术 | 45174篇 |
冶金工业 | 34383篇 |
原子能技术 | 6620篇 |
自动化技术 | 14121篇 |
出版年
2021年 | 2052篇 |
2019年 | 1999篇 |
2018年 | 3678篇 |
2017年 | 3716篇 |
2016年 | 3998篇 |
2015年 | 2232篇 |
2014年 | 3781篇 |
2013年 | 8737篇 |
2012年 | 5677篇 |
2011年 | 7213篇 |
2010年 | 5854篇 |
2009年 | 6486篇 |
2008年 | 6609篇 |
2007年 | 6491篇 |
2006年 | 5569篇 |
2005年 | 5116篇 |
2004年 | 4629篇 |
2003年 | 4554篇 |
2002年 | 4366篇 |
2001年 | 4472篇 |
2000年 | 4184篇 |
1999年 | 4197篇 |
1998年 | 10184篇 |
1997年 | 7181篇 |
1996年 | 5501篇 |
1995年 | 4131篇 |
1994年 | 3598篇 |
1993年 | 3838篇 |
1992年 | 2983篇 |
1991年 | 2995篇 |
1990年 | 2892篇 |
1989年 | 2852篇 |
1988年 | 2865篇 |
1987年 | 2509篇 |
1986年 | 2569篇 |
1985年 | 2854篇 |
1984年 | 2688篇 |
1983年 | 2554篇 |
1982年 | 2300篇 |
1981年 | 2269篇 |
1980年 | 2345篇 |
1979年 | 2359篇 |
1978年 | 2382篇 |
1977年 | 2487篇 |
1976年 | 2876篇 |
1975年 | 2188篇 |
1974年 | 2068篇 |
1973年 | 2166篇 |
1972年 | 1940篇 |
1971年 | 1756篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
161.
Fusing computing and biology expertise, bioinformatics software provides a powerful tool for organizing and mining the vast amounts of data genetics researchers are accumulating. As life scientists and computational scientists interact to create useful bioinformatics software systems, several themes or lessons recur. We identify seven themes: the nature of biological data; data storage, analysis and retrieval; computational modeling and simulation; biologically meaningful information integration; data mining; image processing and visualization; and closing the loop 相似文献
162.
163.
Consideration was given to the decision making procedures based on the fuzzy messages of experts whose preferences on the set of collective decisions can also be fuzzy. 相似文献
164.
165.
I. N. Polandov V. K. Novik O. K. Gulish B. P. Bogomolov V. B. Morozov 《Measurement Techniques》1989,32(9):888-890
Translated from Izmeritel'naya Tekhnika, No. 9, pp. 34–35, September, 1989. 相似文献
166.
Thin films on aluminum-tungsten alloys were prepared by co-deposition of pure aluminum and pure tungsten, each sputtered by an independently controlled magnetron source, on glass and sapphire substrates. Completely amorphous films were obtained in the Al80W20-Al67W33 composition range. Passivity and corrosion behavior of amorphous Al-W alloys were investigated in 1 M deaerated hydrochloric acid solution using polarization and impedance spectroscopy measurements and have been correlated with the properties of pure alloy components. Tungsten and sputter-deposited Al-W thin films are inherently passive materials while aluminum undergoes pitting corrosion in hydrochloric acid solution. The passive film formed at the OCP on each alloy possesses excellent electric and dielectric properties comparable to those of the isolating film on tungsten. The absolute impedance increases with increasing tungsten content in the alloy. According to electrochemical polarization measurements, alloying Al with W in solid solution significantly enhances the material's resistance to pitting corrosion by shifting the breakdown potential above 2000 mV (Al67W33) and lowering the corrosion rate at the OCP by more than two orders of magnitude. The most likely mechanism explaining the passivity of amorphous Al-W alloys, the Solute Vacancy Interaction Model (SVIM), involves the formation of complexes between highly oxidized solute atoms (W+6) and mobile cation vacancies, which restrict the transport of Cl− through the oxide film and inhibit its breakdown in hydrochloric acid solution. The role that film stress relaxation effects and microscopic defects in amorphous Al-W films, of the some composition, and deposited on various substrates play in their corrosion resistance is discussed. 相似文献
167.
168.
169.
V. L. Ozol' L. F. Kandyba N. T. Bychenkov L. A. Zbarskii B. E. Koropov 《Metallurgist》1989,33(8):156-156
Lenin Dnepropetrovsk Pipe Plant. Translated from Metallurg, No. 8, p. 39, August, 1989. 相似文献
170.
A. M. Pristrem N. I. Danilovich V. A. Labunov 《Journal of Engineering Physics and Thermophysics》1987,53(6):1464-1472
By using integral transform methods, an approach is developed to the solution of a problem on the temprature distribution in multilayer structures heated by cw scanning laser radiation, with phase transitions in the layers taken into account.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 53, No. 6, pp. 1000–1010, December, 1987. 相似文献