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   397546篇
  免费   5412篇
  国内免费   1527篇
电工技术   7081篇
综合类   286篇
化学工业   60135篇
金属工艺   14636篇
机械仪表   11469篇
建筑科学   10352篇
矿业工程   1372篇
能源动力   11033篇
轻工业   41159篇
水利工程   3581篇
石油天然气   4855篇
武器工业   6篇
无线电   49080篇
一般工业技术   73452篇
冶金工业   74061篇
原子能技术   7045篇
自动化技术   34882篇
  2021年   2849篇
  2019年   2667篇
  2018年   4276篇
  2017年   4284篇
  2016年   4680篇
  2015年   3440篇
  2014年   5814篇
  2013年   18349篇
  2012年   10342篇
  2011年   14627篇
  2010年   11406篇
  2009年   13086篇
  2008年   13486篇
  2007年   13545篇
  2006年   12189篇
  2005年   11219篇
  2004年   10716篇
  2003年   10390篇
  2002年   9841篇
  2001年   10258篇
  2000年   9448篇
  1999年   10039篇
  1998年   24470篇
  1997年   17248篇
  1996年   13104篇
  1995年   10045篇
  1994年   8605篇
  1993年   8473篇
  1992年   6172篇
  1991年   5901篇
  1990年   5608篇
  1989年   5441篇
  1988年   5312篇
  1987年   4472篇
  1986年   4308篇
  1985年   5189篇
  1984年   4702篇
  1983年   4345篇
  1982年   3990篇
  1981年   4104篇
  1980年   3787篇
  1979年   3644篇
  1978年   3445篇
  1977年   4036篇
  1976年   5138篇
  1975年   2976篇
  1974年   2907篇
  1973年   2989篇
  1972年   2380篇
  1971年   2192篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
No generally accepted principles and guidelines currently exist to help engineers design local interaction mechanisms that result in a desired global behavior. However, several communities have developed ways of approaching this problem in the context of niched application areas. Because the ideas underlying these approaches are often obscured or underemphasized in technical papers, the authors review the role of self-organization in their work. They provide a better picture of the status of the emerging field of self-organizing systems or autonomic computing.  相似文献   
72.
G. C. Bakos   《Applied Energy》2002,72(3-4):609-619
This paper deals with the technical feasibility and economic viability of a grid connected wind-energy conversion system (WECS) used to cover the energy demand of an average habitable dwelling. The various parts of the wind-energy system are described and the useful electrical energy production is determined using a simulation program based on the Monte Carlo method. An economic analysis of the WEC system is performed using a computerized assessment tool. Important financial indices are calculated and financial scenarios investigated.  相似文献   
73.
Elasticity is discussed as an aspect of viscoelasticity, which is described by the tube model. The effects of both crosslinks and entanglements contribute to this model and a discussion of how these effects can be quantified is given. At high enough concentration, entanglements ensure the existence of elastic effects even without crosslinks, and a theory is presented on how this dynamical phase change comes about.  相似文献   
74.
In this letter, a concise process technology is proposed for the first time to enable the fabrication of good quality three-dimensional (3-D) suspended radio frequency (RF) micro-inductors on bulk silicon, without utilizing the lithography process on sidewall and trench-bottom patterning. Samples were fabricated to demonstrate the applicability of the proposed process technology.  相似文献   
75.
'Software defined radio' (SDR) is a technology that will appear in future generations of mobile phones, i.e. following the third-generation mobile phone technology that is currently being defined and developed. Early versions of 'pragmatic' SDR will allow the terminal to be reconfigured at any level of its protocol stack. Ultimately, the 'pure' SDR technology will allow a mobile phone or terminal to have its air interface software configured or reconfigured by other software (or software parameters) that have been downloaded to the terminal, e.g. over the air, or from a remote server via the Internet and one's personal computer (PC). A number of security issues arise with downloaded code that implements the air interface functions, and these may not be obvious simply from looking at the way PC software is updated on-line today. This paper starts with an outline of the code that allows a mobile phone to operate over a particular air interface. This sets the baseline for a discussion of the security issues surrounding the change of this code from one that is fixed and downloaded once only, to code that is reconfigurable during the life of a product.  相似文献   
76.
77.
78.
This paper describes a sequential tripping strategy used in a wide area back-up protection expert system (BPES) to combat situations in which protection relays have maloperated or information is missing. The BPES is an innovative back-up protection scheme designed to prevent the occurrence of widespread blackouts. The BPES evaluates the certainty that transmission lines are likely to be affected by the fault and uses a sequential tripping strategy to isolate the fault if a firm decision is not available due to maloperated relays and/or missing information. The mode of analysis and the sequential tripping strategy ensures that the BPES will clear a fault at minimum risk to the network. An example is included to demonstrate how the certainty factor based sequential tripping strategy is employed by the BPES to clear a fault which occurred on the South Western part of the UK National Grid System  相似文献   
79.
Eliminating the adoption barrier   总被引:1,自引:0,他引:1  
Krueger  C. 《Software, IEEE》2002,19(4):29-31
  相似文献   
80.
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