全文获取类型
收费全文 | 315245篇 |
免费 | 7686篇 |
国内免费 | 1894篇 |
专业分类
电工技术 | 5862篇 |
技术理论 | 5篇 |
综合类 | 1213篇 |
化学工业 | 54453篇 |
金属工艺 | 12091篇 |
机械仪表 | 8799篇 |
建筑科学 | 8355篇 |
矿业工程 | 1777篇 |
能源动力 | 7209篇 |
轻工业 | 34857篇 |
水利工程 | 3405篇 |
石油天然气 | 6227篇 |
武器工业 | 250篇 |
无线电 | 30087篇 |
一般工业技术 | 57654篇 |
冶金工业 | 57638篇 |
原子能技术 | 5931篇 |
自动化技术 | 29012篇 |
出版年
2022年 | 2633篇 |
2021年 | 4102篇 |
2020年 | 2822篇 |
2019年 | 3487篇 |
2018年 | 5341篇 |
2017年 | 5221篇 |
2016年 | 5747篇 |
2015年 | 4346篇 |
2014年 | 6584篇 |
2013年 | 15283篇 |
2012年 | 10733篇 |
2011年 | 13582篇 |
2010年 | 10795篇 |
2009年 | 11216篇 |
2008年 | 11771篇 |
2007年 | 11616篇 |
2006年 | 10020篇 |
2005年 | 8774篇 |
2004年 | 7932篇 |
2003年 | 7316篇 |
2002年 | 7235篇 |
2001年 | 7038篇 |
2000年 | 6647篇 |
1999年 | 6626篇 |
1998年 | 16106篇 |
1997年 | 11747篇 |
1996年 | 8768篇 |
1995年 | 6440篇 |
1994年 | 5790篇 |
1993年 | 5739篇 |
1992年 | 4251篇 |
1991年 | 4049篇 |
1990年 | 4043篇 |
1989年 | 4021篇 |
1988年 | 3756篇 |
1987年 | 3228篇 |
1986年 | 3242篇 |
1985年 | 3642篇 |
1984年 | 3498篇 |
1983年 | 3215篇 |
1982年 | 2884篇 |
1981年 | 3121篇 |
1980年 | 2868篇 |
1979年 | 2951篇 |
1978年 | 2851篇 |
1977年 | 3208篇 |
1976年 | 4412篇 |
1975年 | 2536篇 |
1974年 | 2354篇 |
1973年 | 2414篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
Gomes A. C. S. A. Costa L. C. Brito D. C. Frana R. J. Marques Mnica R. C. 《Polymer Bulletin》2020,77(4):1969-1981
Polymer Bulletin - In this study, we synthesized a new ion-imprinted polymer (IIP) based on introduction of amidoxime groups in acrylonitrile, complexation with Cd2+ ions and polymerization with... 相似文献
62.
A hybrid sorbent material for removal of hydrogen sulfide from air was developed. The material is based on activated carbon and iron compounds obtained from waste iron(II) sulfate(VI) heptahydrate. The iron salt is deposited on the carbonaceous support and subjected to oxidation (Fe2+ to Fe3+) using atmospheric oxygen under alkaline conditions. An effect of H2O2 addition to the process on the composition of the resultant material was also examined. X-ray diffraction (XRD) analyses confirmed easy conversion of waste FeSO4·7H2O to iron oxides Fe3O4 and FeOOH. The activated carbon supporting iron oxides revealed a higher efficiency in H2S elimination from air compared to the commercial activated carbon, without any modification. 相似文献
63.
A. L. Rudenko V. V. Mishakin A. V. Gonchar K. V. Kurashkin A. E. Fomin 《Power Technology and Engineering (formerly Hydrotechnical Construction)》2020,53(6):687-689
At the hydroelectric unit No. 11 of the Nizhnekamsk hydroelectric power plant, the filling wedges of a rotor were investigated by ultrasound in the free st 相似文献
64.
Nurullah Bulut Bahar Atmaca Gülsün Akdemir Evrendilek Sibel Uzuner 《Journal of Food Safety》2020,40(6):e12855
Seed processing technologies are essential for seed safety and functionality through protection of physicochemical quality, pathogen inactivation, aflatoxin detoxification and alleviation of mutagenicity. Design of a pilot-scale unit of pulsed electric fields (PEF) to treat sesame seeds with respect to quality parameters, Aspergillus parasiticus inactivation and aflatoxin reduction as well as alleviation of aflatoxin mutagenicity were prompted in this study. PEF energy ranged from 0.97 to 17.28 J achieved maximum reductions of peroxide value and acidity number of 67.4 and 85.7%, respectively, and did not change color L*, a*, b* and hue values. A 60% reduction of A. parasiticus counts occurred at the maximum PEF energy. Aflatoxins G1, G2, B1, and B2 contents decreased by 94.7, 92.7, 86.9, and 98.7%, respectively. Except for the samples treated by 2.16 J with 100 μg/plate and by 6.80 J with 10 μg/plate, PEF treatment provided elimination of aflatoxin mutagenity. It is concluded that PEF treatment can be used to treat sesame seeds with preservation of physicochemical properties, inactivation of A. parasiticus and decomposition of aflatoxins with reduced mutagenicity. 相似文献
65.
Scientometrics - The interdisciplinary nature of library and information science (LIS) research has been highlighted for some time now. The term “interdisciplinary” is used primarily in... 相似文献
66.
Durmuş Burhanettin Temurtaş Hasan Özyön Serdar 《Neural computing & applications》2020,32(22):17097-17113
Neural Computing and Applications - This study presents the design of a tenth-order multiple feedback Chebyshev low-pass filter (MF-C-LPF). Component selection and gain calculation of filters are... 相似文献
67.
Dorofeyev V. Yu. Sviridova A. N. Svistun L. I. 《Russian Journal of Non-Ferrous Metals》2020,61(3):354-361
Russian Journal of Non-Ferrous Metals - Rolling bearing rings comprise a large reserve for expanding powder metallurgy production. This reserve is being incompletely implemented. The hot forging of... 相似文献
68.
Metallurgical and Materials Transactions B - The process of obtaining titanium tetrachloride (TiCl4) from the quartz-leucoxene concentrate (QLC) from the Yaregskoe oil-titanium field was studied.... 相似文献
69.
70.