全文获取类型
收费全文 | 4152篇 |
免费 | 328篇 |
国内免费 | 195篇 |
专业分类
电工技术 | 256篇 |
综合类 | 268篇 |
化学工业 | 710篇 |
金属工艺 | 223篇 |
机械仪表 | 235篇 |
建筑科学 | 336篇 |
矿业工程 | 125篇 |
能源动力 | 133篇 |
轻工业 | 252篇 |
水利工程 | 80篇 |
石油天然气 | 264篇 |
武器工业 | 25篇 |
无线电 | 443篇 |
一般工业技术 | 495篇 |
冶金工业 | 264篇 |
原子能技术 | 28篇 |
自动化技术 | 538篇 |
出版年
2024年 | 17篇 |
2023年 | 57篇 |
2022年 | 117篇 |
2021年 | 165篇 |
2020年 | 133篇 |
2019年 | 100篇 |
2018年 | 117篇 |
2017年 | 96篇 |
2016年 | 127篇 |
2015年 | 163篇 |
2014年 | 201篇 |
2013年 | 242篇 |
2012年 | 214篇 |
2011年 | 228篇 |
2010年 | 206篇 |
2009年 | 214篇 |
2008年 | 182篇 |
2007年 | 179篇 |
2006年 | 202篇 |
2005年 | 208篇 |
2004年 | 156篇 |
2003年 | 173篇 |
2002年 | 226篇 |
2001年 | 177篇 |
2000年 | 133篇 |
1999年 | 98篇 |
1998年 | 90篇 |
1997年 | 76篇 |
1996年 | 62篇 |
1995年 | 50篇 |
1994年 | 43篇 |
1993年 | 28篇 |
1992年 | 25篇 |
1991年 | 16篇 |
1990年 | 16篇 |
1989年 | 18篇 |
1988年 | 12篇 |
1987年 | 15篇 |
1986年 | 11篇 |
1985年 | 8篇 |
1984年 | 11篇 |
1983年 | 6篇 |
1981年 | 4篇 |
1980年 | 4篇 |
1979年 | 8篇 |
1977年 | 7篇 |
1976年 | 5篇 |
1974年 | 3篇 |
1967年 | 5篇 |
1966年 | 4篇 |
排序方式: 共有4675条查询结果,搜索用时 46 毫秒
1.
Longzhi Li Xiaowei Jiang Zhiguo Bian Jianwei Wang Fumao Wang Zhanlong Song 《Drying Technology》2019,37(2):173-185
Microwave lignite drying with assistance of biomass-derived char was addressed and effect of bio-char on drying rate and energy consumption was investigated in this work. Effective diffusion coefficient and activation energy for the drying process were also analyzed. The results indicated the drying process was largely dependent on the variation of sample temperature. Bio-char originated from pine wood was most favorable for lignite drying, considering its better promoting effect and advanced security. There existed an optimal bio-char addition ratio for drying process at different power. The corresponding optimal ratio was 10% at 231?W and 15% at 385?W, at which the biggest drying rate and the least energy consumption were reached. It was compared lignite drying initiated at 385?W was better for energy conservation. Effective diffusivity was improved and activation energy was simultaneously reduced, with the addition of bio-char. The minimum activation energy was 15.54?W?·?g?1, which was gained at bio-char addition ratio of 10%. The results revealed the effect of bio-char on depressing activation energy could rival that of metal-based additives. The drying process with assistance of microwave and bio-char could present technical and economical benefits on lignite upgrading. 相似文献
2.
3.
4.
6.
7.
8.
9.
10.
This paper reports the results of current fundamental research at the Department of Process Engineering, University of Miskolc on the processing of clean coal from Mecsek bituminous coal, Southern Hungary. The theoretical possibility of the separation of different petrographic components was proven experimentally and their liberation degree was determined based on the petrographic composition, flotation kinetic study of isolated components (groups of components), scanning electron microscopy and microprobe analyses. The mill with stirred ball media was chosen for the ultra-fine liberation of the coal components. It was revealed that along with the liberation of coal components, their surface oxidation and spontaneous agglomeration, entrapping the mineral impurities take place in ultra-fine grinding. This paper discusses the interfacial phenomena occurring in the ultra-fine grinding process and their influence on the flotation. The concept for the advanced preparation of clean coal was developed, tested and proved. The main steps of this concept are the ultra-fine liberation in the stirred-media mill, the de-agglomeration of flocs spontaneously formed during the ultra-fine grinding and the induced (hydrophobic) flocculation with the following two-step flotation in a flotation column. 相似文献