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   866篇
  免费   2篇
电工技术   2篇
化学工业   14篇
机械仪表   3篇
建筑科学   2篇
能源动力   1篇
轻工业   88篇
无线电   273篇
一般工业技术   6篇
冶金工业   443篇
自动化技术   36篇
  2021年   5篇
  2019年   2篇
  2018年   5篇
  2017年   6篇
  2016年   3篇
  2014年   10篇
  2013年   12篇
  2012年   2篇
  2011年   8篇
  2010年   5篇
  2008年   4篇
  2007年   8篇
  2006年   12篇
  2005年   3篇
  2004年   8篇
  2003年   2篇
  2002年   7篇
  2001年   56篇
  2000年   57篇
  1999年   56篇
  1998年   169篇
  1997年   132篇
  1996年   44篇
  1995年   25篇
  1994年   34篇
  1993年   19篇
  1992年   6篇
  1991年   16篇
  1990年   11篇
  1989年   7篇
  1988年   10篇
  1987年   5篇
  1985年   9篇
  1984年   4篇
  1983年   1篇
  1982年   5篇
  1981年   7篇
  1980年   4篇
  1979年   1篇
  1978年   4篇
  1977年   22篇
  1976年   39篇
  1975年   5篇
  1974年   2篇
  1973年   3篇
  1972年   2篇
  1969年   1篇
  1968年   2篇
  1967年   1篇
  1965年   1篇
排序方式: 共有868条查询结果,搜索用时 16 毫秒
1.
2.
3.
The past decade may be regarded as the phase of the fundamental developments in fieldbus systems that were based on the OSI model. Today we are entering a second stage. It is the objective of this issue to present the current state and where the further developments will lead to. This introductory article is intended to give an overview on the subject.  相似文献   
4.
Recently appeared defects on high voltage cables have required an urgent evaluation of the impact of lightning strikes necessary. In some cases overvoltages between the copper wire screen of the cable and earth may appear which cause damages of the cablesheath. Field measurements with a classification of the voltage impulses at the copper wire screen have been made to evaluate the number of events. Additionally a numerical model was developed to study the effects of atmospheric discharges on underground cables with emphasis to the influence on the cablesheath. This numeric method was also applied to estimate the effectiveness of different protection arrangements. This contribution presents evaluation methods for overvoltages of cables and a model used firstly for calculating the stress caused by differential voltages and secondly to determinate the influence of protection measures.  相似文献   
5.
The mechanical properties of totally ischemic hearts of inbred albino rats were studied. The ischemic myocardium was found to be more sensitive to cyclic loads. Energy deficient contracture of cardiomyocytes is a factor which increases the resistance of the myocardium to mechanical effects.  相似文献   
6.
This article illustrates how the hermeneutic analysis of text illuminates how shared understandings affect our interpretations of lean communication in distributed work environments. It is proposed that in contrast to the pessimistic conclusions of media richness theory that lean communication channels cannot support complex or equivocal work tasks, miscommunications are not the result of technology, but rather occur due to a lack of shared understandings among the individuals communicating. An illustrative case study based on fieldwork in franchise organizations is presented to demonstrate the possibilities for how the hermeneutic analysis of coherence, invention, intention, and reference can be used to discover how workers create and recreate shared understandings through text.  相似文献   
7.
8.
Through TCD test, observation on the blood flow dynamics change before and after treatment with 31 cases of the child cerebral atrophy was made. It is found that scalp therapy is able to speed up the blood flow of part artery, especially increase the even blood flow speed of MCA, ACA obviously (P < 0.05), which preliminary shows the mechanism of scalp therapy for child cerebral atrophy mean while. It is found that scalp therapy also has the function to restrain epilepsy.  相似文献   
9.
Qualitative-quantitative simulation is one of the most productive and promising research areas in Artificial Intelligence to emerge in recent years. This method provides an elegant way for an exhaustive analysis of uncertain dynamic systems. The application of the qualitative-quantitative simulation is shown in this paper. The important question about the stability of a quanlitatively described dynamical system is solved by a novel analytic method.  相似文献   
10.
Modern communication systems offer high speed and reliable data transmission services. The quality of these services is achieved by combining coded multi-level modulation techniques and modern digital signal processing (Viterbi-decoding) in the receiver. In this paper we first present an introduction to Trellis Coded Modulation (TCM) and then some new results on unversal techniques adapted for the AWGN-channel as well as for the fading channel. It is shown that TCM is well suited for communication channels with time variant characteristics (e.g. mobile communication channels), especially when our new codes are applied.  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