全文获取类型
收费全文 | 592520篇 |
免费 | 39968篇 |
国内免费 | 20436篇 |
专业分类
电工技术 | 32390篇 |
技术理论 | 78篇 |
综合类 | 35057篇 |
化学工业 | 95371篇 |
金属工艺 | 30851篇 |
机械仪表 | 36662篇 |
建筑科学 | 47947篇 |
矿业工程 | 17901篇 |
能源动力 | 17139篇 |
轻工业 | 34410篇 |
水利工程 | 9806篇 |
石油天然气 | 36262篇 |
武器工业 | 4336篇 |
无线电 | 68507篇 |
一般工业技术 | 70442篇 |
冶金工业 | 32436篇 |
原子能技术 | 5860篇 |
自动化技术 | 77469篇 |
出版年
2024年 | 208篇 |
2023年 | 7894篇 |
2022年 | 11818篇 |
2021年 | 19418篇 |
2020年 | 16915篇 |
2019年 | 19141篇 |
2018年 | 14622篇 |
2017年 | 16803篇 |
2016年 | 13632篇 |
2015年 | 19559篇 |
2014年 | 26220篇 |
2013年 | 33780篇 |
2012年 | 35241篇 |
2011年 | 39881篇 |
2010年 | 34295篇 |
2009年 | 33348篇 |
2008年 | 32554篇 |
2007年 | 31360篇 |
2006年 | 33043篇 |
2005年 | 29487篇 |
2004年 | 19437篇 |
2003年 | 17223篇 |
2002年 | 15488篇 |
2001年 | 14130篇 |
2000年 | 14639篇 |
1999年 | 17350篇 |
1998年 | 15267篇 |
1997年 | 12625篇 |
1996年 | 11750篇 |
1995年 | 10052篇 |
1994年 | 8203篇 |
1993年 | 6075篇 |
1992年 | 4808篇 |
1991年 | 3695篇 |
1990年 | 2892篇 |
1989年 | 2414篇 |
1988年 | 1913篇 |
1987年 | 1286篇 |
1986年 | 964篇 |
1985年 | 707篇 |
1984年 | 464篇 |
1983年 | 399篇 |
1982年 | 374篇 |
1981年 | 267篇 |
1980年 | 248篇 |
1979年 | 182篇 |
1978年 | 119篇 |
1977年 | 127篇 |
1976年 | 179篇 |
1975年 | 71篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
Fire Technology - Water mist is considered as a potential alternative to halon in fire extinguishing applications. However, penetration is remarkably reduced due to the rapid decay of momentum in... 相似文献
2.
Fire Technology - The critical velocity is the minimum velocity blowing towards the fire seat in tunnels to reduce the length of back-layering to zero, and it has been extensively adopted in the... 相似文献
3.
Fire Technology - Deep convolutional networks have significantly improved the performance of smoke image recognition. However, the trained spatially-shared weights are applied to all pixels... 相似文献
4.
Fire Technology - The current research on individual risks mainly focuses on the individual risk considering a single fire or the spatial distribution of multiple fires. It is more realistic to... 相似文献
5.
6.
Fire Technology - A co-flow water mist system is considered a clean and efficient emergency handling measure for preventing and controlling the leakage of hazardous gas. To reveal the coupling... 相似文献
7.
Liu Wei Zhao Fusheng Kong Meiling Yin Songfeng Wang Huiying Liu Xiaoying 《Fire Technology》2022,58(5):2811-2823
Fire Technology - The use of perfluorinated hexanone as a fire extinguishing agent for lithium-ion batteries (LIBs) has been steadily increasing in China in recent years. It successfully handles... 相似文献
8.
Fire Technology - With 110 kV oil-immersed transformer as the platform, in this paper, we build a full-scale test platform covering 6 fire extinguishing (fire control) methods and different... 相似文献
9.
Physical inactivity poses growing threats to the Chinese population,associated with booming urbanization and unfriendly living environment in recent years.This paper is a systematic review to investigate the neighborhood built environment factors correlated with physical activity in the Chinese population,including children and adolescents,adults,and the elderly.The Web of Science has been searched for articles in English,and the China National Knowledge Infrastructure has been searched for articles in Chinese.A total of 35 articles published before January 2020 have been included in this review.Then these articles are studied with a focus on six major aspects-transportation,density,design,diversity,amenity,and walkability–finding that the neighborhood built environment factors related to physical activity vary across age groups and different types of neighborhoods.In the context of refined community governance,future research should make further explorations from aspects including different resident groups,local characteristics of neighborhoods,built environment characteristics,research design,and other relevant variables. 相似文献
10.
Jiang Guo Xing-Yu Wang Yong Zhao Chen-Yi Hou Xu Zhu Yin-Di Cai Zhu-Ji Jin Ren-Ke Kang 《先进制造进展(英文版)》2022,10(3):368-381
The tool state exerts a strong influence on surface quality and profile accuracy during precision/ultraprecision machining. However, current on-machine measurement methods cannot precisely obtain the tool nose radius and wear. This study therefore investigated the onmachine measurement of tool nose radius on the order of hundreds of microns and wear on the order of a few microns to tens of microns during precision/ultra-precision machining using the edge reversal method. To provide the necessary replication, pure aluminum and pure copper soft metal substrates were evaluated, with pure copper exhibiting superior performance. The feasibility of the measurement method was then demonstrated by evaluating the replication accuracy using a 3D surface topography instrument; the measurement error was only 0.1%. The wear of the cutting tool was measured using the proposed method to obtain the maximum values for tool arc wear, flank wear, and wear depth of 3.4 lm, 73.5 lm and 3.7 lm, respectively.The full text can be downloaded at https://link.springer.com/article/10.1007/s40436-022-00397-y 相似文献