全文获取类型
收费全文 | 47449篇 |
免费 | 7202篇 |
国内免费 | 13篇 |
专业分类
电工技术 | 780篇 |
综合类 | 3篇 |
化学工业 | 17584篇 |
金属工艺 | 323篇 |
机械仪表 | 722篇 |
建筑科学 | 1780篇 |
矿业工程 | 1篇 |
能源动力 | 998篇 |
轻工业 | 7418篇 |
水利工程 | 342篇 |
石油天然气 | 51篇 |
无线电 | 7383篇 |
一般工业技术 | 12128篇 |
冶金工业 | 612篇 |
原子能技术 | 9篇 |
自动化技术 | 4530篇 |
出版年
2024年 | 20篇 |
2023年 | 19篇 |
2022年 | 39篇 |
2021年 | 307篇 |
2020年 | 2305篇 |
2019年 | 4490篇 |
2018年 | 3128篇 |
2017年 | 3471篇 |
2016年 | 4246篇 |
2015年 | 3959篇 |
2014年 | 3867篇 |
2013年 | 4998篇 |
2012年 | 2679篇 |
2011年 | 2302篇 |
2010年 | 2619篇 |
2009年 | 2493篇 |
2008年 | 2038篇 |
2007年 | 1866篇 |
2006年 | 1635篇 |
2005年 | 1363篇 |
2004年 | 1328篇 |
2003年 | 1296篇 |
2002年 | 1241篇 |
2001年 | 1086篇 |
2000年 | 1057篇 |
1999年 | 444篇 |
1998年 | 65篇 |
1997年 | 48篇 |
1996年 | 26篇 |
1995年 | 21篇 |
1994年 | 23篇 |
1993年 | 22篇 |
1992年 | 18篇 |
1991年 | 15篇 |
1990年 | 13篇 |
1989年 | 11篇 |
1988年 | 10篇 |
1987年 | 10篇 |
1986年 | 9篇 |
1985年 | 13篇 |
1984年 | 12篇 |
1983年 | 10篇 |
1982年 | 9篇 |
1981年 | 5篇 |
1980年 | 5篇 |
1977年 | 4篇 |
1976年 | 4篇 |
1974年 | 2篇 |
1973年 | 4篇 |
1890年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
111.
112.
M. BraAbrem A. Najari H.‐A. Ho J.‐F. Gravel P. Nobert D. Boudreau M. Leclerc 《Advanced materials (Deerfield Beach, Fla.)》2006,18(20)
The cover image depicts biochips based on responsive nanoaggregates made from stoichiometric complexes between a cationic polythiophene and an appropriate DNA aptamer. These structures undergo a conformational transition from an unfolded to a folded (G‐quadruplex) structure in the presence of a specific target protein that results in a significant increase of the fluorescence intensity, as reported on p. 2703 by Leclerc and co‐workers. 相似文献
113.
Hot band annealing is known to be a prerequisite for good magnetic properties irrespective of manufacturing methods in grain‐oriented Fe‐3 wt.% Si electrical steels. In this study, the effects of hot band annealing on magnetic properties were investigated in 3% grain‐oriented electrical steels of low soluble AI contents and one‐stage cold rolling. Microstructure and precipitate distribution were compared with hot band annealing conditions. Secondary recrystallization behaviour with hot band annealing condition was also discussed. 相似文献
114.
115.
116.
117.
118.
119.
Video servers are essential in video‐on‐demand and other multimedia applications. In this paper, we present our high‐performance clustered CBR video server, Odyssey. Odyssey is a server connecting PCs with switched Ethernet. It provides efficient support for normal play and interactive browsing functions such as fast‐forward and fast‐backward. We designed a set of algorithms for scheduling, synchronization and admission control, which results in a high utilization of resources. Odyssey is able to deliver a large number of video streams. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
120.
Heinz‐Dieter Bürger 《真空研究与实践》2004,16(2):67-70
The use of the high evaporation enthalpy of water is one of the oldest technologies of refrigeration for food preservation used by the mankind. One could nearly celebrate the true 5000th anniversary of this technology. Nowadays we call the refrigeration by evaporation from wet surfaces “adiabatic refrigeration”, it regulates, for instance, our body heat by evaporating sweat. After the introduction of some vacuum pumps into the experimental scientific works, 250 years ago, namely in Great Britan, the modern form of “artificial” refrigeration began its career, the evaporation of liquids under the absence of permanent gasses in vacuum. The vacuum refrigeration has been nearly abruptly stopped by the development of compression refrigeration processes, about 150 years ago. Only after world war 2, a reintroduction of vacuum refrigeration began again. Now, at the beginning of the 3. milennium, there are good chances for recovering terrain. 相似文献