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   690篇
  免费   31篇
  国内免费   1篇
电工技术   8篇
化学工业   257篇
金属工艺   28篇
机械仪表   19篇
建筑科学   37篇
矿业工程   5篇
能源动力   21篇
轻工业   51篇
水利工程   9篇
石油天然气   2篇
无线电   30篇
一般工业技术   118篇
冶金工业   33篇
原子能技术   7篇
自动化技术   97篇
  2022年   20篇
  2021年   32篇
  2020年   9篇
  2019年   5篇
  2018年   20篇
  2017年   23篇
  2016年   24篇
  2015年   15篇
  2014年   31篇
  2013年   58篇
  2012年   24篇
  2011年   44篇
  2010年   21篇
  2009年   48篇
  2008年   28篇
  2007年   28篇
  2006年   19篇
  2005年   21篇
  2004年   16篇
  2003年   20篇
  2002年   15篇
  2001年   16篇
  2000年   14篇
  1999年   4篇
  1998年   3篇
  1997年   4篇
  1996年   8篇
  1995年   6篇
  1994年   7篇
  1993年   4篇
  1992年   7篇
  1990年   5篇
  1989年   5篇
  1988年   7篇
  1987年   9篇
  1986年   7篇
  1985年   9篇
  1984年   11篇
  1983年   11篇
  1982年   9篇
  1981年   9篇
  1980年   9篇
  1979年   6篇
  1977年   3篇
  1976年   8篇
  1975年   2篇
  1974年   4篇
  1973年   3篇
  1970年   2篇
  1956年   2篇
排序方式: 共有722条查询结果,搜索用时 546 毫秒
661.
At high ionic strength the ion pair (NiPy2+4, nX?) or complex (NiPy4X2), n = 0, 1, 2; X? = Cl?, Br?, SCN?, N?3, F?, NO?3, ClO?4; is adsorbed at the surface of mercury electrode. Under specified conditions in chloride, bromide, and thiocyanates solutions the electroreduction is preceded by a crystallization of a complex on the electrode surface. The inductive role of specifically coadsorbed Cl? ions is discussed.  相似文献   
662.
663.
We present an extension of the resource-constrained multi-product scheduling problem for an automated guided vehicle (AGV) served flow shop, where multiple material handling transport modes provide movement of work pieces between machining centers in the multimodal transportation network (MTN). The multimodal processes behind the multi-product production flow executed in an MTN can be seen as processes realized by using various local periodically functioning processes. The considered network of repetitively acting local transportation modes encompassing MTN’s structure provides a framework for multimodal processes scheduling treated in terms of optimization of the AGVs fleet scheduling problem subject to fuzzy operation time constraints. In the considered case, both production takt and operation execution time are described by imprecise data. The aim of the paper is to present a constraint propagation (CP) driven approach to multi-robot task allocation providing a prompt service to a set of routine queries stated in both direct and reverse way. Illustrative examples taking into account an uncertain specification of robots and workers operation time are provided.  相似文献   
664.
To make optimal use of sustainable energy, domestic electricity consumption should shift to match local supply conditions. Energy management systems (EMS) are a new sustainable technology that can help to disrupt consumers’ habits concerning electricity consumption, whilst reinforcing desired behaviours. This research examined the factors that influence the likelihood that people will shift their electricity consumption to match sustainable supply. Twenty-one interviews were conducted with households who had used the EMS ‘Smart Wash’ for several months. The findings showed that the likelihood of behaviour change is influenced by a combination of the user's motivation, specific contextual factors and the design of the EMS. Based on these results, several recommendations are given for the future design of EMSs.

Practitioner Summary: Energy management systems (EMS) are a new technology that encourages people to shift electricity consumption to match local solar supply. Interviews among users of an EMS showed that the likelihood of behaviour change is influenced by the combination of the user's motivation, contextual factors and the EMS design.  相似文献   
665.
Tuning compiler optimizations for rapidly evolving hardware makes porting and extending an optimizing compiler for each new platform extremely challenging. Iterative optimization is a popular approach to adapting programs to a new architecture automatically using feedback-directed compilation. However, the large number of evaluations required for each program has prevented iterative compilation from widespread take-up in production compilers. Machine learning has been proposed to tune optimizations across programs systematically but is currently limited to a few transformations, long training phases and critically lacks publicly released, stable tools. Our approach is to develop a modular, extensible, self-tuning optimization infrastructure to automatically learn the best optimizations across multiple programs and architectures based on the correlation between program features, run-time behavior and optimizations. In this paper we describe Milepost GCC, the first publicly-available open-source machine learning-based compiler. It consists of an Interactive Compilation Interface (ICI) and plugins to extract program features and exchange optimization data with the cTuning.org open public repository. It automatically adapts the internal optimization heuristic at function-level granularity to improve execution time, code size and compilation time of a new program on a given architecture. Part of the MILEPOST technology together with low-level ICI-inspired plugin framework is now included in the mainline GCC. We developed machine learning plugins based on probabilistic and transductive approaches to predict good combinations of optimizations. Our preliminary experimental results show that it is possible to automatically reduce the execution time of individual MiBench programs, some by more than a factor of 2, while also improving compilation time and code size. On average we are able to reduce the execution time of the MiBench benchmark suite by 11% for the ARC reconfigurable processor. We also present a realistic multi-objective optimization scenario for Berkeley DB library using Milepost GCC and improve execution time by approximately 17%, while reducing compilation time and code size by 12% and 7% respectively on Intel Xeon processor.  相似文献   
666.
Action rule is an implication rule that shows the expected change in a decision value of an object as a result of changes made to some of its conditional values. An example of an action rule is ‘credit card holders of young age are expected to keep their cards for an extended period of time if they receive a movie ticket once a year’. In this case, the decision value is the account status, and the condition value is whether the movie ticket is sent to the customer. The type of action that can be taken by the company is to send out movie tickets to young customers. The conventional action rule discovery algorithms build action rules from existing classification rules. This paper discusses an agglomerative strategy that generates the shortest action rules directly from a decision system. In particular, the algorithm can be used to discover rules from an incomplete decision system where attribute values are partially incomplete. As one of the testing domains for our research we take HEPAR system that was built through a collaboration between the Institute of Biocybernetics and Biomedical Engineering of the Polish Academy of Sciences and physicians at the Medical Center of Postgraduate Education in Warsaw, Poland. HEPAR was designed for gathering and processing clinical data on patients with liver disorders. Action rules will be used to construct the decision-support module for HEPAR.  相似文献   
667.
We describe a fast connected components labeling algorithm using a region coloring approach. It computes region attributes such as size, moments, and bounding boxes in a single pass through the image. Working in the context of real-time pupil detection for an eye tracking system, we compare the time performance of our algorithm with a contour tracing-based labeling approach and a region coloring method developed for a hardware eye detection system. We find that region attribute extraction performance exceeds that of these comparison methods. Further, labeling each pixel, which requires a second pass through the image, has comparable performance.  相似文献   
668.
The density and surface tension measurements of the Sn3.13Ag0.74Cu liquid alloys with 2, 3, 4, 15, 30, 50 and 75 at.% In additions were conducted in the temperature range from 431 K up to 1209 K by dilatometric technique and the maximum bubble pressure method, respectively. The results obtained in both techniques exhibited 2%–3% scattering of experimental errors, similarly to the previously investigated In–Sn and Sn–Ag–In systems. This was due to the very similar surface tension and density values of pure indium and tin. The experimental surface tensions were compared with calculated ones using data of the constituent systems, (a) by means of thermodynamic method of Butler, and (b) by the temperature and concentration relation of the surface tension. The improvement of wettability in liquid alloys containing different In additions was confirmed with a sessile drop method in the temperature interval 523 K–593 K up to 1800 s. The wetting angles decreased with temperature and increasing In concentrations in the solders from ∼37°37° for the solder without In at 523 K down to ∼22°22° for the solder with 75 at.% In at 593 K.  相似文献   
669.
With the rapid development of technologies, many production systems and modes has been advanced with respect to manufacturing, management and information fields. The paper deals with the problem of the implementation of an autonomous industrial mobile robot in real-world industrial applications in which all these fields are considered, namely mobile robot technology, planning and scheduling and communication. A methodology for implementation consisting of: a mobile robot system design (Little Helper prototype), an appropriate industrial application (multiple-part feeding), an implementation concept for the industrial application (the Bartender Concept), a mathematical model and a genetic algorithm-based heuristic is proposed. Furthermore, in order for the mobile robot to work properly in a flexible (cloud-based) manufacturing environment, the communications and exchange of data between the mobile robot with other manufacturing systems and shop-floor operators are addressed in the methodology. The proposed methodology provides insight into how mobile robot technology and abilities contribute to cloud manufacturing systems. A real-world demonstration at an impeller production line in a factory and computational experiments are conducted to demonstrate the effectiveness of the proposed methodology.  相似文献   
670.
Positive linear systems on arbitrary time scales are studied. The theory developed in the paper unifies and extends concepts and results known for continuous-time and discrete-time systems. A necessary and sufficient condition for a linear system on a time scale to be positive is presented. Properties of positive reachable sets are investigated and characterizations of various controllability properties are presented. A modified Gram matrix of the system is used to state necessary and sufficient condition of positive reachability of a positive system on an arbitrary time scale.  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