首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   487432篇
  免费   6446篇
  国内免费   2376篇
电工技术   8455篇
综合类   891篇
化学工业   71771篇
金属工艺   18008篇
机械仪表   14520篇
建筑科学   12263篇
矿业工程   2149篇
能源动力   12982篇
轻工业   45799篇
水利工程   4785篇
石油天然气   6879篇
武器工业   79篇
无线电   60291篇
一般工业技术   94246篇
冶金工业   89883篇
原子能技术   10081篇
自动化技术   43172篇
  2021年   3711篇
  2020年   2876篇
  2019年   3515篇
  2018年   5768篇
  2017年   5870篇
  2016年   6330篇
  2015年   4388篇
  2014年   7404篇
  2013年   22125篇
  2012年   12635篇
  2011年   17661篇
  2010年   13766篇
  2009年   15666篇
  2008年   16474篇
  2007年   16490篇
  2006年   14712篇
  2005年   13493篇
  2004年   13055篇
  2003年   12733篇
  2002年   12103篇
  2001年   12457篇
  2000年   11544篇
  1999年   12195篇
  1998年   29512篇
  1997年   20828篇
  1996年   15954篇
  1995年   12180篇
  1994年   10677篇
  1993年   10620篇
  1992年   7679篇
  1991年   7278篇
  1990年   7063篇
  1989年   6843篇
  1988年   6499篇
  1987年   5600篇
  1986年   5511篇
  1985年   6422篇
  1984年   5856篇
  1983年   5384篇
  1982年   5039篇
  1981年   5069篇
  1980年   4888篇
  1979年   4581篇
  1978年   4483篇
  1977年   5042篇
  1976年   6462篇
  1975年   3806篇
  1974年   3674篇
  1973年   3752篇
  1972年   3049篇
排序方式: 共有10000条查询结果,搜索用时 132 毫秒
991.
An employee's failure to differentiate himself or herself from the perceived attitudes of another is at the heart of much stress in organizations. The world of family systems psychology identifies a dysfunctional process, called psychological fusion, which stems from insufficient self-definition by an individual and results in a dependency upon others to meet an innate need to feel accepted. People suffering from psychological fusion perceive any criticism as a threat, making it impossible for them to receive the critical feedback that is necessary for growth. To experience intrinsic motivation, people require a sense of relative self-determination and competence. This paper argues that much as employers take an interest in such emotional health issues as substance abuse and stress, they should also address psychological fusion; the paper offers methods for dealing with this interpersonal communications issue  相似文献   
992.
The paper examines collaborative writing practices students in the Air Force Institute of Technology's Graduate School of Logistics and Acquisition Management use to produce team-authored theses. In analyzing how student writing teams plan, execute, and assess writing activities, the researchers identify and describe some of the forms that collaboration takes, thereby successfully connecting their work within a broader research continuum concerning collaborative writing, particularly when applied in academic settings  相似文献   
993.
994.
995.
996.
997.
998.
A distributed circuit-switched approach for supporting the deployment of high speed wireless personal communication services in urban areas through the interconnection of base stations via metropolitan area networks (MANs) is proposed. Broadband MANs minimize traffic congestion by dynamic sharing of link capacity and by serving as distributed switches for partitioning call control functions. While the DQDB protocol readily supports distributed packet-switching over the IEEE 802.6 MAN, isochronous traffic such as voice and video is best supported by circuit-switched connections. The authors present an enhanced bi-state pre-arbitrated (PA) transport mechanism, and associated call control and handoff management techniques, which enable distributed circuit-switching over the MAN. These capabilities are not currently addressed in the 802.6 standards. The bi-state PA transport mechanism facilitates statistical multiplexing of variable rate isochronous traffic sources. The network capacity is constrained by the call setup delay performance, and is analyzed by simulations. Alternative signaling architectures, involving different placements of call control network elements, are evaluated. The effects of erasure nodes, and close bus versus open bus architectures, are considered. The overlap inter-MAN call setup procedure is proposed to reduce delays. Different call handoff procedures are formulated according to the type of handoff and the resulting change in call connectivity. Most handoffs are intra-MAN, requiring simple procedures with short delays  相似文献   
999.
Presents an overview of problems involved in introducing ISDN and new services in the public network of Poland. The technical aspects of the assumed network and services development strategy are considered. The focus is on development alternatives and the process of establishing national requirements for the development  相似文献   
1000.
Considering the given situation in the Hungarian telecommunications infrastructure and the prompt demands for advanced services, this paper describes an individual solution to provide intelligent services in the mixed analog and partly digitalized Hungarian public telephone network. The preIN system is based on co-located stand-alone units equipped with SSP/SCP functionality  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号