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   344篇
  免费   15篇
  国内免费   6篇
电工技术   59篇
综合类   48篇
化学工业   2篇
金属工艺   2篇
机械仪表   3篇
建筑科学   7篇
矿业工程   2篇
能源动力   1篇
无线电   141篇
一般工业技术   10篇
冶金工业   8篇
自动化技术   82篇
  2023年   1篇
  2022年   1篇
  2020年   1篇
  2019年   2篇
  2018年   1篇
  2017年   3篇
  2016年   2篇
  2015年   3篇
  2014年   13篇
  2013年   26篇
  2012年   18篇
  2011年   17篇
  2010年   20篇
  2009年   21篇
  2008年   15篇
  2007年   12篇
  2006年   14篇
  2005年   16篇
  2004年   14篇
  2003年   28篇
  2002年   27篇
  2001年   23篇
  2000年   13篇
  1999年   20篇
  1998年   10篇
  1997年   8篇
  1996年   10篇
  1995年   7篇
  1994年   4篇
  1993年   2篇
  1991年   2篇
  1989年   1篇
  1988年   1篇
  1987年   2篇
  1985年   2篇
  1984年   2篇
  1983年   1篇
  1982年   1篇
  1955年   1篇
排序方式: 共有365条查询结果,搜索用时 62 毫秒
101.
讨论了电力线载波通道所包含的高频电缆、结合滤波器、耦合电容、线路阻波器的检查方法.  相似文献   
102.
电力线高速数据通信系统电磁辐射及应用性能的研究   总被引:11,自引:1,他引:11  
分析了PLC系统电磁辐射的机理,根据典型的PLC系统电磁辐射测试结果探讨了CISPR22、FCC Part15、NB30、MPTl557的适应性。给出了PLC系统实际应用性能的测试结果。最后针对我国的实际应用情况,对包括运行稳定性、电磁兼客性等PLC系统的多方面应用性能进行了初步探讨。  相似文献   
103.
低压电力线载波通信信道传输特性分析   总被引:6,自引:1,他引:6  
深入研究和分析了低压电力线的信道特性,解释了应用中遇到的问题,提出了相应的宏观解决方案。  相似文献   
104.
电力市场化是电力工业发展的方向。为强化线损管理工作,提高供电企业经济效益,阐述了电力网电能损耗的组成,分析了线损过高的主要原因。通过线损计算分析,提出了电网降损的措施,重点指出健全线损管理体系,加大技术降损力度是解决此问题的关键。  相似文献   
105.
研究开发配电网的电力线网络通信系统,提出了适于配网自动化的OFDM通信系统方案。以OFDM收/发器INT51X1和嵌入式ARM处理器为核心,完成了通信终端的具体设计。  相似文献   
106.
In recent years reliability growth models have gained a dominant role in the evaluation of the reliability of software products. However, their application to the quality assurance process of the software of a highly complex system such as a telecommunications switching system often shows that it is then possible to get accurate results only when some months of operation have elapsed. It is then impossible to give an answer to the typical questions which arise during the quality assurance phase: ‘Is the software ready for release? How long will it take before it is ready?’. This paper describes a multi-variable (MV) model which was developed to overcome the above limitation by providing a better model of the quality assurance process. A case study is presented, and a comparison is made between the results obtained by applying existing reliability growth models and the MV-model to it. Besides attaining surprising accuracy in its predictions and in measuring the reliability of the product, the MV-model also tries to tackle a different kind of question: ‘How is it possible to improve the effectiveness of testing?’.  相似文献   
107.
针对3GPP提出的3G安全结构中重点描述的网络接入安全技术规范,深入研究了UMTS安全结构.分析了UMTS网络接入安全特性和安全机制,并对未来发展趋势进行展望.  相似文献   
108.
Routing optimisation in some types of networks requires the calculation of the minimal cost pair of disjoint paths such that the cost functions associated with the arcs in the two paths are different. An exact algorithm for solving this NP-complete problem is proposed, based on a condition which guarantees that the optimal path pair cost has been obtained. This optimality condition is based on the calculation of upper and lower bounds on the optimal cost. A formal proof of the correctness of the algorithm is described. Extensive experimentation is presented to show the effectiveness of the algorithm, including a comparison with an integer linear programming formulation.  相似文献   
109.
This paper describes two exact algorithms for the joint problem of object placement and request routing in a content distribution network (CDN). A CDN is a technology used to efficiently distribute electronic content throughout an existing Internet Protocol network. The problem consists of replicating content on the proxy servers and routing the requests for the content to a suitable proxy server in a CDN such that the total cost of distribution is minimized. An upper bound on end-to-end object transfer time is also taken into account. The problem is formulated as a nonlinear integer programming formulation which is linearized in three different ways. Two algorithms, one based on Benders decomposition and the other based on Lagrangean relaxation and decomposition, are described for the solution of the problem. Computational experiments are conducted by comparing the proposed linearizations and the two algorithms on randomly generated Internet topologies.  相似文献   
110.
In this paper, we propose a tabu search (TS) algorithm for the global planning problem of third generation (3G) universal mobile telecommunications system (UMTS) networks. This problem is composed of three NP-hard subproblems: the cell, the access network and the core network planning subproblems. Therefore, the global planning problem consists in selecting the number, the location and the type of network nodes (including the base stations, the radio network controllers, the mobile switching centers and the serving GPRS (General Packet Radio Service) support nodes) as well as the interconnections between them. After describing our metaheuristic, a systematic set of experiments is designed to assess its performance. The results show that quasi-optimal solutions can be obtained with the proposed approach.  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