全文获取类型
收费全文 | 309856篇 |
免费 | 3722篇 |
国内免费 | 714篇 |
专业分类
电工技术 | 6195篇 |
综合类 | 560篇 |
化学工业 | 46758篇 |
金属工艺 | 10324篇 |
机械仪表 | 8821篇 |
建筑科学 | 7907篇 |
矿业工程 | 863篇 |
能源动力 | 8570篇 |
轻工业 | 31084篇 |
水利工程 | 2535篇 |
石油天然气 | 3669篇 |
武器工业 | 8篇 |
无线电 | 39697篇 |
一般工业技术 | 58462篇 |
冶金工业 | 56669篇 |
原子能技术 | 5458篇 |
自动化技术 | 26712篇 |
出版年
2021年 | 2281篇 |
2019年 | 2141篇 |
2018年 | 3610篇 |
2017年 | 3451篇 |
2016年 | 3541篇 |
2015年 | 2542篇 |
2014年 | 4441篇 |
2013年 | 14280篇 |
2012年 | 7369篇 |
2011年 | 10116篇 |
2010年 | 7904篇 |
2009年 | 9136篇 |
2008年 | 9605篇 |
2007年 | 9588篇 |
2006年 | 8515篇 |
2005年 | 7891篇 |
2004年 | 7760篇 |
2003年 | 7497篇 |
2002年 | 7337篇 |
2001年 | 7544篇 |
2000年 | 7205篇 |
1999年 | 7548篇 |
1998年 | 17657篇 |
1997年 | 12833篇 |
1996年 | 10099篇 |
1995年 | 7873篇 |
1994年 | 7206篇 |
1993年 | 6904篇 |
1992年 | 5286篇 |
1991年 | 5067篇 |
1990年 | 4933篇 |
1989年 | 4781篇 |
1988年 | 4673篇 |
1987年 | 3887篇 |
1986年 | 4008篇 |
1985年 | 4719篇 |
1984年 | 4275篇 |
1983年 | 4021篇 |
1982年 | 3601篇 |
1981年 | 3761篇 |
1980年 | 3457篇 |
1979年 | 3418篇 |
1978年 | 3227篇 |
1977年 | 3814篇 |
1976年 | 4847篇 |
1975年 | 2780篇 |
1974年 | 2660篇 |
1973年 | 2675篇 |
1972年 | 2215篇 |
1971年 | 1963篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
161.
Rajoo R. Lim S.S. Wong E.H. Hnin W.Y. Seah S.K.W. Tay A.A.O. Iyer M. Tummala R.R. 《Advanced Packaging, IEEE Transactions on》2008,31(2):377-385
A wafer level packaging technique has been developed with an inherent advantage of good solder joint co-planarity suitable for wafer level testing. A suitable weak metallization scheme has also been established for the detachment process. During the fabrication process, the compliancy of the solder joint is enhanced through stretching to achieve a small shape factor. Thermal cycling reliability of these hourglass-shaped, stretch solder interconnections has been found to be considerably better than that of the conventional spherical-shaped solder bumps. 相似文献
162.
Ann R Thryft 《电子设计技术》2008,15(7):78-78,80,82,84,86
数年来,具有10Gbps速度的下一代以太网一直处于即将成为主流的状况。一段时间以来,网络的某些区域已在使用光学技术,并且随着流量的增加,对10GbE数据速率的需求正在增长。但是,需要一种比上一代以太网复杂许多的技术,用于在100m长的铜缆上运行10GbE。这一要求导致了昂贵的MAC(媒体访问控制器)和交换芯片,以及昂贵而又不方便的PHY层接口芯片,由此限制了快速LAN用于那些覆盖数据中心内较短距离的高性能应用。 相似文献
163.
In this time of flat, team-based and technology-enabled organizations the effectiveness of communication and team leadership practices will be more important than ever before. Therefore, we believe that some of the earlier, time-tested classic works on group dynamics and leadership are worthy of re-reading. We are particularly impressed by how relevant one of the oldest classics, Benne and Sheats' (1948) article on functional roles of group members, remains to this day. 相似文献
164.
165.
R. A. Borzooei M. Bakhshi M. Mashinchi 《Soft Computing - A Fusion of Foundations, Methodologies and Applications》2008,12(8):739-749
In this paper, we study the lattice structure of some fuzzy algebraic systems such as (G-)fuzzy groups, some fuzzy ordered
algebras and fuzzy hyperstructures. We prove that under suitable conditions, these structures form a distributive or modular
lattice.
This research partially is supported by the “ Fuzzy Systems and its Applications Center of Excelence, Shahid Bahonar University
of Kerman, Iran”. 相似文献
166.
Tomer A. Goldin L. Kuflik T. Kimchi E. Schach S.R. 《IEEE transactions on pattern analysis and machine intelligence》2004,30(9):601-612
We propose a model that enables software developers to systematically evaluate and compare all possible alternative reuse scenarios. The model supports the clear identification of the basic operations involved and associates a cost component with each basic operation in a focused and precise way. The model is a practical tool that assists developers to weigh and evaluate different reuse scenarios, based on accumulated organizational data, and then to decide which option to select in a given situation. The model is currently being used at six different companies for cost-benefit analysis of alternative reuse scenarios; we give a case study that illustrates how it has been used in practice. 相似文献
167.
Age assessment and control of the reliability of the coolant flow-rate measurement system of the RBMK-1500 reactor at the Ignalina nuclear power plant are examined. A statistical analysis is made of the data obtained from measurements of the techanical characteristics of SHADR-32M flow meters. A mathematical model of the aging of flow meters and reliability estimates is constructed. A strategy is developed for replacing SHADR; this strategy makes it possible to support the required relaibility of the entire coolant flow-rate measurement system. 相似文献
168.
Digital evidence is inherently weak. New evidence-gathering technologies-digital black boxes-must be developed and deployed to support investigations of irreproducible events such as digitally signing a document or electronically casting a ballot. 相似文献
169.
Yanqing Ji Hao Ying John Yen Shizhuo Zhu Daniel C. Barth‐Jones Richard E. Miller R. Michael Massanari 《国际智能系统杂志》2007,22(8):827-845
Discovering unknown adverse drug reactions (ADRs) in postmarketing surveillance as early as possible is highly desirable. Nevertheless, current postmarketing surveillance methods largely rely on spontaneous reports that suffer from serious underreporting, latency, and inconsistent reporting. Thus these methods are not ideal for rapidly identifying rare ADRs. The multiagent systems paradigm is an emerging and effective approach to tackling distributed problems, especially when data sources and knowledge are geographically located in different places and coordination and collaboration are necessary for decision making. In this article, we propose an active, multiagent framework for early detection of ADRs by utilizing electronic patient data distributed across many different sources and locations. In this framework, intelligent agents assist a team of experts based on the well‐known human decision‐making model called Recognition‐Primed Decision (RPD). We generalize the RPD model to a fuzzy RPD model and utilize fuzzy logic technology to not only represent, interpret, and compute imprecise and subjective cues that are commonly encountered in the ADR problem but also to retrieve prior experiences by evaluating the extent of matching between the current situation and a past experience. We describe our preliminary multiagent system design and illustrate its potential benefits for assisting expert teams in early detection of previously unknown ADRs. © 2007 Wiley Periodicals, Inc. Int J Int Syst 22: 827–845, 2007. 相似文献
170.