全文获取类型
收费全文 | 114600篇 |
免费 | 3758篇 |
国内免费 | 2011篇 |
专业分类
电工技术 | 2533篇 |
技术理论 | 1篇 |
综合类 | 4603篇 |
化学工业 | 16771篇 |
金属工艺 | 6672篇 |
机械仪表 | 5070篇 |
建筑科学 | 4545篇 |
矿业工程 | 1590篇 |
能源动力 | 1936篇 |
轻工业 | 5956篇 |
水利工程 | 1890篇 |
石油天然气 | 2045篇 |
武器工业 | 244篇 |
无线电 | 12722篇 |
一般工业技术 | 19693篇 |
冶金工业 | 3895篇 |
原子能技术 | 666篇 |
自动化技术 | 29537篇 |
出版年
2024年 | 139篇 |
2023年 | 519篇 |
2022年 | 1063篇 |
2021年 | 1497篇 |
2020年 | 1169篇 |
2019年 | 977篇 |
2018年 | 15307篇 |
2017年 | 14323篇 |
2016年 | 10911篇 |
2015年 | 2022篇 |
2014年 | 2047篇 |
2013年 | 2257篇 |
2012年 | 5379篇 |
2011年 | 11772篇 |
2010年 | 10337篇 |
2009年 | 7512篇 |
2008年 | 8654篇 |
2007年 | 9471篇 |
2006年 | 1697篇 |
2005年 | 2371篇 |
2004年 | 2027篇 |
2003年 | 2044篇 |
2002年 | 1586篇 |
2001年 | 996篇 |
2000年 | 811篇 |
1999年 | 679篇 |
1998年 | 466篇 |
1997年 | 346篇 |
1996年 | 349篇 |
1995年 | 276篇 |
1994年 | 206篇 |
1993年 | 156篇 |
1992年 | 84篇 |
1991年 | 84篇 |
1990年 | 54篇 |
1989年 | 55篇 |
1988年 | 47篇 |
1969年 | 24篇 |
1968年 | 43篇 |
1967年 | 33篇 |
1966年 | 42篇 |
1965年 | 44篇 |
1963年 | 28篇 |
1960年 | 30篇 |
1959年 | 37篇 |
1958年 | 37篇 |
1957年 | 36篇 |
1956年 | 34篇 |
1955年 | 63篇 |
1954年 | 68篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
211.
Paolo Detti 《Journal of Scheduling》2008,11(3):205-212
A variant of the High Multiplicity Multiprocessor Scheduling Problem with C job lengths is considered, in which jobs can be processed only by machines not greater than a given index. When C=2, polynomial algorithms are proposed, for the feasibility version of the problem and for maximizing the number of scheduled
jobs. 相似文献
212.
213.
Thomas Deiß 《International Journal on Software Tools for Technology Transfer (STTT)》2008,10(4):347-352
When deploying TTCN-3 at Nokia, we converted two TTCN-2 test systems to TTCN-3. We explain to which extend we have been able
to do the conversion automatically. The conversion tool used provided a syntactically and semantically correct conversion
of the TTCN-2 code. We define some improvements made on the tool to increase readability and maintainability of the resulting
code. We cover aspects of converting also the non-TTCN-2 parts and describe the experiences we made as a set of lessons learnt. 相似文献
214.
215.
Computer vision systems 总被引:1,自引:0,他引:1
216.
Tong Fang Mohsen A. Jafari Stephen C. Danforth Ahmad Safari 《Machine Vision and Applications》2003,15(2):63-75
This paper presents the concept of a process signature for the use of online signature analysis and defect detection in the layered manufacturing (LM) of ceramic sensors and actuators. To achieve the high quality of parts built by the fused deposition of ceramics (FDC), an online process-monitoring system is implemented to detect the processing defects. Using a process signature extracted from the image of a layer captured by the monitoring system, an ideal image is created that is then compared to the original image to detect and identify the defects. Some results of signature analysis and defect detection for single-material and multi-material parts are also presented.Received: 22 July 1999, Accepted: 21 October 2001, Published online: 29 October 2003
Correspondence to: Mohsen A. JafariThis work was supported by the Office of Naval Research under grant # N-0014-96-1-1175. Ref. US Patent # S-5738817, April 14, 1998. 相似文献
217.
218.
219.
e-Government systems differ from commercial information systems (IS) in that they frequently encompass strategic goals that go beyond efficiency, effectiveness and economy, and include political and social objectives such as trust in government, social inclusion, community regeneration, community well-being and sustainability. Designing e-Government systems that help to meet these objectives is a significant challenge for the future. This paper develops an evaluative design framework for e-Government projects that complements traditional approaches to IS evaluation. The framework is based upon Moor's concept of public value. It focuses upon citizens' and clients' experiences of service provision and service outcomes as contributors to the formation of public trust. Trust is shown to be related to the extent to which people feel that an e-Government service enhances their sense of being well-informed, gives them greater personal control, and provides them with a sense of influence or contingency. The framework's development and validation are founded upon analyses of a two live case studies in south-east England and London, U.K. 相似文献
220.
Ahmad Nozad Golikand Elaheh Lohrasbi Mohammad Ghannadi Maragheh Mehdi Asgari 《Journal of Applied Electrochemistry》2008,38(6):869-874
The effect of carbon surface oxidation on platinum supported carbon particles (Pt/C) with nitric acid was investigated by
cyclic voltammetry, electrochemical impedance spectroscopy, polarization experiments and chronoamperometry. Cyclic voltammograms,
polarization curves and electrochemical impedance spectra showed that the treated catalyst had much larger active surface
area and higher ionic conductivity than the untreated catalyst, and provided enhanced performance for oxygen reduction. The
formation of acidic groups was examined by IR spectra. The Pt/C surface oxidation had a large effect on the performance of
a gas diffusion electrode for oxygen reduction reaction. 相似文献