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   1278篇
  免费   68篇
  国内免费   4篇
电工技术   22篇
综合类   1篇
化学工业   217篇
金属工艺   46篇
机械仪表   27篇
建筑科学   65篇
矿业工程   11篇
能源动力   45篇
轻工业   134篇
水利工程   8篇
石油天然气   12篇
无线电   151篇
一般工业技术   189篇
冶金工业   156篇
原子能技术   20篇
自动化技术   246篇
  2023年   16篇
  2022年   14篇
  2021年   24篇
  2020年   18篇
  2019年   22篇
  2018年   27篇
  2017年   33篇
  2016年   37篇
  2015年   30篇
  2014年   35篇
  2013年   91篇
  2012年   55篇
  2011年   83篇
  2010年   48篇
  2009年   70篇
  2008年   78篇
  2007年   57篇
  2006年   65篇
  2005年   52篇
  2004年   37篇
  2003年   29篇
  2002年   29篇
  2001年   26篇
  2000年   21篇
  1999年   23篇
  1998年   33篇
  1997年   26篇
  1996年   11篇
  1995年   14篇
  1994年   14篇
  1993年   25篇
  1992年   13篇
  1991年   9篇
  1990年   12篇
  1989年   15篇
  1988年   10篇
  1987年   10篇
  1986年   6篇
  1985年   10篇
  1984年   13篇
  1983年   11篇
  1982年   14篇
  1981年   11篇
  1980年   8篇
  1979年   14篇
  1977年   3篇
  1976年   7篇
  1975年   8篇
  1974年   7篇
  1973年   5篇
排序方式: 共有1350条查询结果,搜索用时 906 毫秒
81.
This paper attempts to trace the development of energy consumption in the UK during the process of industrialization. First a quantitative overview of the relationship between energy consumption and economic growth for the period 1700–1975 is presented. An examination of the factors affecting relations between economic growth and energy consumption is then presented. This is divided into two main periods: pre-1800 and 1800–1975. The discussion of pre-1800 energy consumption is mainly concerned with coal use, while a more detailed account is given of developments in the later period.  相似文献   
82.
Human exposure to electromagnetic fields emitted by mobile phones is characterised by the Specific Absorption Rate (sar). This value corresponds to therf power absorbed by unitary mass of the equivalent tissue. It represents the basic restriction used to define limit of human exposure torf electromagnetic fields. Academic and industrial labs have contributed through thecomobio project to define international standards for mobile phones certification.  相似文献   
83.
Statistical Models for Data Mining   总被引:1,自引:0,他引:1  
We review the background to the papers presented in this special issue and give a short introduction to each. We also briefly describe the workshop on Statistical models for data mining, held in Pavia (Italy), in October 2000, where the papers were presented.  相似文献   
84.
Agent-based simulation has been a popular technique in modeling and analyzing electricity markets in recent years. The main objective of this paper is to study existing agent-based simulation packages for electricity markets. We first provide an overview of electricity markets and briefly introduce the agent-based simulation technique. We then investigate several general-purpose agent-based simulation tools. Next, we review four popular agent-based simulation packages developed for electricity markets and several agent-based simulation models reported in the literature. We compare all the reviewed packages and models and identify their common features and design issues. Based on the study, we describe an agent-based simulation framework for electricity markets to facilitate the development of future models for electricity markets.  相似文献   
85.
Gebis  Joe Patterson  David 《Computer》2007,40(4):68-75
A vector case study shows how new functionality can be added to extend the 80times86 and PowerPC architectures to support a full vector architecture, primarily by enhancing their multimedia extensions to provide a better model for compilers and an easier-to-understand model for programmers  相似文献   
86.
When ambulances are engaged in responding to emergency calls, the ability to respond quickly to future calls is considerably compromised. The available ambulances are typically relocated to reestablish maximal coverage. We present a two-stage stochastic optimization model for the ambulance redeployment problem that minimizes the number of relocations over a planning horizon while maintaining an acceptable service level. We conduct computational testing based on the real historical data from the Region of Waterloo Emergency Medical Services. The results show that the optimal relocation strategies can be computed within 40 s of computational time for a desired service level of 90%.  相似文献   
87.
A common claim in the literature on Information Systems' implementation in the context of less developed economies or so-called “developing countries” is that the “Western” technology is at odds with the local cultural context, in particular it is believed to mismatch local rationality in the sense of the accepted ways of doing things. In this paper we investigate IS implementation in a company based in a “non-Western” context compared with IS adoption in another company in a “Western” country context. Seen as a particular form of decision-making, the adoption and implementation processes are analysed drawing on the literature on decision-making, rationality in “Western” and “non-Western” contexts. Presenting evidence from these two contexts we argue that multiple forms of rationality exist in any context and that national culture is only one aspect of actors' as well as researchers' sense-making of activities in any given context. Linking the cases back the literature we reflect on the implications of our findings for cross-cultural research of IT implementation.  相似文献   
88.

Behavioural modelling of physical systems from observations of their input/output behaviour is an important task in engineering. Such models are needed for fault monitoring as well as intelligent control of these systems. The paper addresses one subtask of behavioural modelling, namely the selection of input variables to be used in predicting the behaviour of an output variable. A technique that is well suited for qualitative behavioural modelling and simulation of physical systems is Fuzzy Inductive Reasoning (FIR), a methodology based on General System Theory. Yet, the FIR modelling methodology is of exponential computational complexity, and therefore, it may be useful to consider other approaches as booster techniques for FIR. Different variable selection algorithms: the method of the unreconstructed variance for the best reconstruction, methods based on regression coefficients (OLS, PCR and PLS) and other methods as Multiple Correlation Coefficients (MCC), Principal Components Analysis (PCA) and Cluster analysis are discussed and compared to each other for use in predicting the behaviour of a steam generator. The different variable selection algorithms previously named are then used as booster techniques for FIR. Some of the used linear techniques have been found to be non-effective in the task of selecting variables in order to compute a posterior FIR model. Methods based on clustering seem particularly well suited for pre-selecting subsets of variables to be used in a FIR modelling and simulation effort.  相似文献   
89.
90.
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