全文获取类型
收费全文 | 607670篇 |
免费 | 15152篇 |
国内免费 | 4375篇 |
专业分类
电工技术 | 13527篇 |
技术理论 | 10篇 |
综合类 | 5040篇 |
化学工业 | 93074篇 |
金属工艺 | 23679篇 |
机械仪表 | 19413篇 |
建筑科学 | 18495篇 |
矿业工程 | 4097篇 |
能源动力 | 16746篇 |
轻工业 | 55811篇 |
水利工程 | 6693篇 |
石油天然气 | 12999篇 |
武器工业 | 564篇 |
无线电 | 68491篇 |
一般工业技术 | 112442篇 |
冶金工业 | 110097篇 |
原子能技术 | 11301篇 |
自动化技术 | 54718篇 |
出版年
2022年 | 4959篇 |
2021年 | 8202篇 |
2020年 | 6137篇 |
2019年 | 6745篇 |
2018年 | 10659篇 |
2017年 | 10500篇 |
2016年 | 10805篇 |
2015年 | 8819篇 |
2014年 | 13280篇 |
2013年 | 29489篇 |
2012年 | 19996篇 |
2011年 | 25763篇 |
2010年 | 20463篇 |
2009年 | 22048篇 |
2008年 | 22428篇 |
2007年 | 21815篇 |
2006年 | 19155篇 |
2005年 | 17361篇 |
2004年 | 16031篇 |
2003年 | 15572篇 |
2002年 | 14595篇 |
2001年 | 14499篇 |
2000年 | 13653篇 |
1999年 | 14694篇 |
1998年 | 35587篇 |
1997年 | 24969篇 |
1996年 | 19249篇 |
1995年 | 14397篇 |
1994年 | 12461篇 |
1993年 | 11840篇 |
1992年 | 8487篇 |
1991年 | 7834篇 |
1990年 | 7611篇 |
1989年 | 7337篇 |
1988年 | 6720篇 |
1987年 | 5936篇 |
1986年 | 5789篇 |
1985年 | 6370篇 |
1984年 | 5990篇 |
1983年 | 5231篇 |
1982年 | 4972篇 |
1981年 | 5037篇 |
1980年 | 4772篇 |
1979年 | 4646篇 |
1978年 | 4437篇 |
1977年 | 5416篇 |
1976年 | 7130篇 |
1975年 | 3820篇 |
1974年 | 3576篇 |
1973年 | 3704篇 |
排序方式: 共有10000条查询结果,搜索用时 953 毫秒
41.
Heiba Zein K. Mohamed Mohamed Bakr Farag Noura M. Badawi Ali 《Journal of Materials Science: Materials in Electronics》2022,33(13):10388-10398
Journal of Materials Science: Materials in Electronics - Nano Mn0.95M0.05S (M ≡ Cu, Mg) samples were produced using molten salt solid state reaction method. Rietveld analysis of X-ray... 相似文献
42.
Rudenko A. I. Nishchik A. P. Otrokh E. A. Terekh A. M. 《Journal of Engineering Physics and Thermophysics》2022,95(1):206-212
Journal of Engineering Physics and Thermophysics - Results of investigation into the influence of a corrosion process on thermotechnical characteristics of heat pipes of low-temperature range are... 相似文献
43.
Radiochemistry - Magnetically modified waste bark of the Aegle marmelos tree was prepared by using green synthesis method and was used in a batch system for U(VI) removal from aqueous solution. The... 相似文献
44.
Kamar M. S. Shalan A. S. Youssef W. M. Hussein A. E. M. Khawassek Y. M. Taha M. H. 《Radiochemistry》2022,64(2):244-256
Radiochemistry - Ferrugination, sericitization, desulfitization, chloritization, and kaolinitization of hydrothermal origin are the main wall rock alterations occurring within the NNW shear zones... 相似文献
45.
Laís D. Silva Fernanda C. Puosso Viviane O. Soares Oscar Peitl Filho Simone do R.F. Sabino Francisco C. Serbena Murilo C. Crovace Edgar D. Zanotto 《Ceramics International》2021,47(13):18720-18731
Bioactive glasses and glass-ceramics (GCs) effectively regenerate bone tissue, however most GCs show improved mechanical properties. In this work, we developed and tested a rarely studied bioactive glass composition (24.4K2O-26.9CaO-46.1SiO2-2.6P2O5 mol%, identified as 45S5-K) with different particle sizes and heating rates to obtain a sintered GC that combines good fracture strength, low elastic modulus, and bioactivity. We analyzed the influence of the sintering processing conditions in the elastic modulus, Vickers microhardness, density, and crystal phase formation in the GC. The best GC shows improved properties compared with its parent glass. This glass achieves a good densification degree with a two-step viscous flow sintering approach and the resulting GC shows as high bioactivity as that of the standard 45S5 Bioglass®. Furthermore, the GC elastic modulus (56 GPa) is relatively low, minimizing stress shielding. Therefore, we unveiled the glass sintering behavior with concurrent crystallization of this complex bioactive glass composition and developed a potential GC for bone regeneration. 相似文献
46.
Wenlong Song Shoujun Wang Yang Lu Xuan Zhang Zixiang Xia Kai Sun Guangming Xin 《Ceramics International》2021,47(9):12631-12640
To enhance the tribological performance of Si3N4/TiC ceramics, MoS2/PTFE composite coatings were deposited on the ceramic substrate through spraying method. The micrographs and basic properties of the MoS2/PTFE coated samples were investigated. Dry sliding friction experiments against WC/Co ball were performed with the coated ceramics and traditional ones. These results showed that the composite coatings could significantly reduce the friction coefficient of ceramics, and protect the substrate from adhesion wear. The primary tribological mechanisms of the coated ceramics were abrasive wear, coating spalling and delamination, and the tribological property was transited from slight wear to serious wear with the increase of load because of the lower surface hardness and shear strength. The possible mechanisms for the effects of MoS2/PTFE composite coatings on the friction performance of ceramics were discussed. 相似文献
47.
Russian Engineering Research - The modernization of manufacturing by the comprehensive application of digital technology—in both production and management—is considered. Principles are... 相似文献
49.
Romero-Garcés A. Salles De Freitas R. Marfil R. Vicente-Chicote C. Martínez J. Inglés-Romero J. F. Bandera A. 《Multimedia Tools and Applications》2022,81(3):3603-3628
Multimedia Tools and Applications - The design of robots capable of operating autonomously in changing and unstructured environments, requires using complex software architectures in which,... 相似文献
50.
Belov M. I. Anashin D. V. Kabdin N. E. Storchevoy V. F. Sudnik Yu. A. 《Russian Engineering Research》2022,42(11):1110-1116
Russian Engineering Research - The stability of robot-mower motion in a specific direction is considered. The direction is regulated by means of an angular sensor and a programmable controller... 相似文献