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   2101篇
  免费   10篇
电工技术   10篇
化学工业   75篇
金属工艺   17篇
机械仪表   11篇
建筑科学   45篇
矿业工程   11篇
能源动力   22篇
轻工业   39篇
水利工程   9篇
石油天然气   3篇
无线电   127篇
一般工业技术   96篇
冶金工业   1580篇
原子能技术   1篇
自动化技术   65篇
  2023年   4篇
  2021年   10篇
  2019年   5篇
  2018年   7篇
  2015年   10篇
  2014年   5篇
  2013年   30篇
  2012年   20篇
  2011年   29篇
  2010年   23篇
  2009年   17篇
  2008年   19篇
  2007年   19篇
  2006年   14篇
  2005年   17篇
  2004年   13篇
  2003年   16篇
  2002年   10篇
  2001年   6篇
  2000年   5篇
  1999年   52篇
  1998年   429篇
  1997年   263篇
  1996年   170篇
  1995年   101篇
  1994年   105篇
  1993年   102篇
  1992年   23篇
  1991年   38篇
  1990年   32篇
  1989年   36篇
  1988年   55篇
  1987年   38篇
  1986年   20篇
  1985年   35篇
  1984年   8篇
  1983年   12篇
  1982年   17篇
  1981年   17篇
  1980年   19篇
  1979年   8篇
  1978年   10篇
  1977年   69篇
  1976年   109篇
  1975年   7篇
  1974年   9篇
  1973年   4篇
  1972年   6篇
  1968年   3篇
  1965年   3篇
排序方式: 共有2111条查询结果,搜索用时 0 毫秒
61.
In this article, we summarize the deployment of the Air Force Weather (AFW) HPC11 system at Oak Ridge National Laboratory (ORNL) including the process followed to successfully complete acceptance testing of the system. HPC11 is the first HPE/Cray EX 3000 system that has been successfully released to its user community in a federal facility. HPC11 consists of two identical 800-node supercomputers, Fawbush and Miller, with access to two independent and identical lustre parallel file systems. HPC11 is equipped with Slingshot 10 interconnect technology and relies on the HPE Performance Cluster Manager software for system configuration. ORNL has a clearly defined acceptance testing process used to ensure that every new system deployed can provide the necessary capabilities to support user workloads. We worked closely with HPE and AFW to develop a set of tests that used the United Kingdom's Meteorological Office's Unified Model and 4-dimensional variational data assimilation. We also included benchmarks and applications from the Oak Ridge Leadership Computing Facility portfolio to fully exercise the HPE/Cray programming environment and evaluate the functionality and performance of the system. Acceptance testing of HPC11 required parallel execution of each element on Fawbush and Miller. In addition, careful coordination was needed to ensure successful acceptance of the newly deployed lustre file systems alongside the compute resources. In this work, we present test results from specific system components and provide an overview of the issues identified, challenges encountered, and the lessons learned along the way.  相似文献   
62.
Knowledge conceptualization tool   总被引:3,自引:0,他引:3  
Knowledge acquisition is one of the most important and problematic aspects of developing knowledge-based systems. Many automated tools have been introduced in the past, however, manual techniques are still heavily used. Interviewing is one of the most commonly used manual techniques for a knowledge acquisition process, and few automated support tools exist to help knowledge engineers enhance their performance. The paper presents a knowledge conceptualization tool (KCT) in which the knowledge engineer can effectively retrieve, structure, and formalize knowledge components, so that the resulting knowledge base is accurate and complete. The KCT uses information retrieval technique to facilitate conceptualization, which is one of the human intensive activities of knowledge acquisition. Two information retrieval techniques employing best-match strategies are used: vector space model and probabilistic ranking principle model. A prototype of the KCT was implemented to demonstrate the concept. The results from KCT are compared with the outputs from a manual knowledge acquisition process in terms of amount of information retrieved and the process time spent. An analysis of the results shows that the process time to retrieve knowledge components (e.g., facts, rules, protocols, and uncertainty) of KCT is about half that of the manual process, and the number of knowledge components retrieved from knowledge acquisition activities is four times more than that retrieved through a manual process  相似文献   
63.
Recent research in mobile robot navigation make it feasible to utilize autonomous robots in service fields. But, such applications require more than just navigation. To operate in a peopled environment, robots should recognize and act according to human social behavior. In this paper, we present the design and implementation of one such social behavior: a robot that stands in line much as people do. The system employs stereo vision to recognize lines of people, and uses the concept of personal space for modeling the social behavior. Personal space is used both to detect the end of a line and to determine how much space to leave between the robot and the person in front of it. Our model of personal space is based on measurements from people forming lines. We demonstrate our ideas with a mobile robot navigation system that can purchase a cup of coffee, even if people are waiting in line for service.  相似文献   
64.
The outcome of this work is a knowledge-based associate ergonomic tool that assists in determining visibility of stationary small objects critical to the work environment. The Luchlesh and Moss detection solid, a design handbook guideline, accounts for non-search visibility in terms of three fundamental variables — visual angle, brightness and contrast. To reduce the difficulty of using the solid in its current form, this effort first quantified the empirical relationships of the solid. The intelligent system building tool, Exsys, was then employed: (1) to convert the results into rules for a knowledge base, and (2) to generate a tool called the Visual Detectability Analysis Associate. An efficient, convenient and easy to use ergonomic design tool is now available that determines visibility of small stationary objects in work environments where viewing time may be limited, but visual search is not required. In current use by a company to solve visibility problems encountered in system design, the VDAA tool has demonstrated beneficial savings in both time and effort.  相似文献   
65.
There is growing interest among internal information technology (IT) departments in implementing a certified quality management system (QMS). This paper examines the forces that have influenced organizations that supply development services to adopt QMS models and explores the relevance of these forces to internal IT developers. The perceptions of internal developers regarding the value of QMS in addressing these forces were studied using a multiple case study involving four organizations. The results suggest that while the reasons given by external developers concern mainly the marketing advantages of adopting a QMS, internal developers envisage the major advantage to be an improvement in the development process.  相似文献   
66.
This paper describes a set of tools that enables developers to log and analyze the run-time behavior of distributed control systems. A feature of the tools is that they can be applied to distributed systems. The logging tools enable developers to instrument C or C++ programs so that data indicating state changes can be logged automatically in a variety of formats. In particular, run-time data from distributed systems can be synchronized into a single relational database. Tools are also provided for visualizing the logged data. Analysis to verify correct program behavior is done using a new interval logic that is described in this paper. The logic enables system engineers to express temporal specifications for the autonomous control program that are then checked against the logged data. The data logging, visualization, and interval logic analysis tools are all fully implemented. Results are given from a NASA distributed autonomous control system application.  相似文献   
67.
68.
WIN 63843, a Picornavirus replication inhibitor, is physically and chemically stable in the solid state, to light, elevated temperature, and humidity. This 3-ary15-trifluoromethyl disubstituted 1,2,4-oxadiazole compound has very low water solubility but is highly soluble in ethanol and in safflower seed and corn oils. Solubility in the vegetable oils is doubled by the synergistic effect of ethanol at the 16% alcohol concentration. Vegetuble oil solutions of WIN 63843 are thermally stable but react slowly in the presence of light resulting in an amidoxime compound (WIN 65489) formed by opening of the 1,2,4-oxadiazole ring. This reaction does not occur in oil solutions containing small concentrations of ethanol. Of biophannaceutical interest, the addition of ethanol or PEG-400 solutions of WIN 63843 to human gastric fluid resulted in oily droplet formation whereas crystals form upon addition of these solutions to water. Also, the compound is greater than 8,000 times more soluble in human gastric fluid.  相似文献   
69.
70.
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