全文获取类型
收费全文 | 4018篇 |
免费 | 360篇 |
国内免费 | 453篇 |
专业分类
电工技术 | 234篇 |
综合类 | 227篇 |
化学工业 | 283篇 |
金属工艺 | 122篇 |
机械仪表 | 188篇 |
建筑科学 | 12篇 |
矿业工程 | 27篇 |
能源动力 | 94篇 |
轻工业 | 17篇 |
水利工程 | 3篇 |
石油天然气 | 9篇 |
武器工业 | 47篇 |
无线电 | 2269篇 |
一般工业技术 | 984篇 |
冶金工业 | 31篇 |
原子能技术 | 74篇 |
自动化技术 | 210篇 |
出版年
2024年 | 11篇 |
2023年 | 45篇 |
2022年 | 55篇 |
2021年 | 98篇 |
2020年 | 96篇 |
2019年 | 103篇 |
2018年 | 82篇 |
2017年 | 133篇 |
2016年 | 139篇 |
2015年 | 126篇 |
2014年 | 210篇 |
2013年 | 254篇 |
2012年 | 213篇 |
2011年 | 271篇 |
2010年 | 222篇 |
2009年 | 236篇 |
2008年 | 242篇 |
2007年 | 271篇 |
2006年 | 283篇 |
2005年 | 266篇 |
2004年 | 222篇 |
2003年 | 235篇 |
2002年 | 162篇 |
2001年 | 146篇 |
2000年 | 149篇 |
1999年 | 101篇 |
1998年 | 64篇 |
1997年 | 59篇 |
1996年 | 55篇 |
1995年 | 37篇 |
1994年 | 40篇 |
1993年 | 37篇 |
1992年 | 40篇 |
1991年 | 31篇 |
1990年 | 24篇 |
1989年 | 19篇 |
1988年 | 21篇 |
1987年 | 4篇 |
1986年 | 6篇 |
1984年 | 4篇 |
1983年 | 2篇 |
1982年 | 4篇 |
1981年 | 2篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 3篇 |
1976年 | 1篇 |
1975年 | 3篇 |
1974年 | 1篇 |
1959年 | 1篇 |
排序方式: 共有4831条查询结果,搜索用时 31 毫秒
11.
12.
13.
L. Sheeney‐Haj‐Ichia S. Pogorelova Y. Gofer I. Willner 《Advanced functional materials》2004,14(5):416-424
Three different configurations of Au‐nanoparticle/CdS‐nanoparticle arrays are organized on Au/quartz electrodes for enhanced photocurrent generation. In one configuration, Au‐nanoparticles are covalently linked to the electrode and the CdS‐nanoparticles are covalently linked to the bare Au‐nanoparticle assembly. The resulting photocurrent, φ = 7.5 %, is ca. 9‐fold higher than the photocurrent originating from a CdS‐nanoparticle layer that lacks the Au‐nanoparticles, φ = 0.8 %. The enhanced photocurrent in the Au/CdS nanoparticle array is attributed to effective charge separation of the electron–hole pair by the injection of conduction‐band electrons from the CdS‐ to the Au‐nanoparticles. Two other configurations involving electrostatically stabilized bipyridinium‐crosslinked Au/CdS or CdS/Au nanoparticle arrays were assembled on the Au/quartz crystal. The photocurrent quantum yields in the two systems are φ = 10 % and φ = 5 %, respectively. The photocurrents in control systems that include electrostatically bridged Au/CdS or CdS/Au nanoparticles by oligocationic units that lack electron‐acceptor units are substantially lower than the values observed in the analogous bipyridinium‐bridged systems. The enhanced photocurrents in the bipyridinium‐crosslinked systems is attributed to the stepwise electron transfer of conduction‐band electrons to the Au‐nanoparticles by the bipyridinium relay bridge, a process that stabilizes the electron–hole pair against recombination and leads to effective charge separation. 相似文献
14.
介绍了当前国际上流行的用半导体可饱和吸收镜来对固体激光器、光纤激光器和半导体激光器进行被动锁模的方法,阐述了半导体可饱和吸收镜用来作为被动锁模吸收体的原理,并介绍了如何利用金属有机气相淀积(MOCVD)技术生长各种波长激光器所需要的半导体可饱和吸收镜. 相似文献
15.
MATLAB在红外可视化分析中的应用 总被引:1,自引:0,他引:1
MATLAB是一个操作简捷、功能强大的数学辅助软件,在红外专业的可视化分析中具有很大的应用空间。介绍了MATLAB在黑体辐射理论、探测器器件分析中的具体使用。 相似文献
16.
Chih-Wea Wang Chi-Feng Wu Jin-Fu Li Cheng-Wen Wu Tony Teng Kevin Chiu Hsiao-Ping Lin 《Journal of Electronic Testing》2002,18(6):637-647
In this paper we propose a novel built-in self-test (BIST) design for embedded SRAM cores. Our contribution includes a compact and efficient BIST circuit with diagnosis support and an automatic diagnostic system. The diagnosis module of our BIST circuit can capture the error syndromes as well as fault locations for the purposes of repair and fault/failure analysis. In addition, our design provides programmability for custom March algorithms with lower hardware cost. The combination of the on-line programming mode and diagnostic system dramatically reduces the effort in design debugging and yield enhancement. We have designed and implemented test chips with our BIST design. Experimental results show that the area overhead of the proposed BIST design is only 2.4% for a 128 KB SRAM, and 0.65% for a 2 MB one. 相似文献
17.
18.
A model for preventive maintenance operations and forecasting 总被引:2,自引:1,他引:1
Equipment costs constitute the greatest majority of overall costs for semiconductor manufacturing. Therefore, maintaining
high equipment availability has been regarded as one of the major goals in the industry. The ability to forecast correctly
equipment preventive maintenance (PM) timing requirements not only can help optimizing equipment uptime but also minimizing
negative impacts on manufacturing production efficiency. This research used grey theory and evaluation diagnosis to construct
a PM forecasting model for prediction of PM timing of various machines. The results showed significant improvements of PM
timing predictions compared to the existing method based on experience and an alternative method proposed by Li and Chang
(Semiconductor Manufacturing Technology Workshop 2002: 10–11, pp. 275–277) for the same fab cases.
Received: June 2005 / Accepted: December 2005 相似文献
19.
20.
本文基于计算机技术和现代测量技术,介绍了一种虚拟仪器-机车大功率整流管试验台的研制。该试验台根据LMS自适应算法,模拟实际工作环境,自适应地控制试验过程,并对试验数据应用小波分析技术分析处理,得到机车大功率整流管准确而全面的性能参数,具有自动化程度高、试验结果可靠性高的优点。本文主要介绍试验数据处理和软件设计。 相似文献