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   488921篇
  免费   97892篇
  国内免费   68177篇
电工技术   53080篇
技术理论   3篇
综合类   53795篇
化学工业   62063篇
金属工艺   44270篇
机械仪表   28521篇
建筑科学   35885篇
矿业工程   22695篇
能源动力   15224篇
轻工业   56852篇
水利工程   17074篇
石油天然气   21893篇
武器工业   7377篇
无线电   61244篇
一般工业技术   55057篇
冶金工业   17929篇
原子能技术   6436篇
自动化技术   95592篇
  2024年   4412篇
  2023年   9258篇
  2022年   16449篇
  2021年   20385篇
  2020年   18899篇
  2019年   23578篇
  2018年   25160篇
  2017年   28018篇
  2016年   26947篇
  2015年   30866篇
  2014年   33789篇
  2013年   36316篇
  2012年   40847篇
  2011年   39055篇
  2010年   36940篇
  2009年   33346篇
  2008年   32164篇
  2007年   31157篇
  2006年   27111篇
  2005年   22744篇
  2004年   20532篇
  2003年   14925篇
  2002年   14099篇
  2001年   12626篇
  2000年   10702篇
  1999年   7025篇
  1998年   5052篇
  1997年   4359篇
  1996年   4070篇
  1995年   4054篇
  1994年   3260篇
  1993年   3008篇
  1992年   2871篇
  1991年   2131篇
  1990年   1665篇
  1989年   1594篇
  1988年   1199篇
  1987年   431篇
  1986年   372篇
  1985年   278篇
  1984年   191篇
  1983年   157篇
  1982年   179篇
  1981年   196篇
  1980年   204篇
  1976年   238篇
  1975年   216篇
  1972年   238篇
  1971年   132篇
  1960年   205篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
Fuzzy logic was first suggested as the mechanism by which humans drive cars. This paper addresses the use of fuzzy logic and algorithms towards the intelligent autonomous motion control of land vehicles. To cope with vehicle complexities, internal parametric changes, and with unpredictable environmental effects, the controllers that are presented, whilst heuristic in nature, are self-organizing or self-learning in that they generate automatically by observation an experiential rule base that models the vehicle, and via an appropriate performance index an optimal control rule base that is robust to large parametric changes. The methodology presented is applicable to any complex process which is too difficult to model or control using conventional methods, or which has relied on the experience of a human operator. An overview of fuzzy logic and static fuzzy logic control (akin to expert systems) is provided, together with illustrative examples.  相似文献   
22.
介绍I/A’S系统在巨化热电厂八号50MW供热机组上应用实例,并从DCS系统的整体设计到实现的功能、控制效果等多方面进行了分折,总结了调试和运行经验。  相似文献   
23.
This paper presents different approaches which enable a data base management system to obtain a plausible fuzzy estimate for an attribute value of an item for which the information is not explicitly stored in the data base. This can be made either by a kind of analogical reasoning from information about particular items or by means of expert rules which specify the (fuzzy) sets of possible values of the attribute under consideration, for various classes of items. Another kind of expert rules enables the system to compute an estimate from the attribute value of another item provided that, in other respects, this latter item sufficiently resembles the item, the value of which we are interested in; then these expert rules are used either for controlling the analogical reasoning process or for enlarging the scope of application of the first kind of expert rules. The different approaches are discussed in the framework of possibility theory.  相似文献   
24.
首钢外购焦炭质量恶化后的高炉生产实践   总被引:2,自引:0,他引:2  
张思斌  王涛  李颖 《炼铁》2004,23(1):18-21
针对焦炭质量劣化的状况,高炉操作以活跃炉缸为主,从上下部调剂入手,采取疏导煤气、控制合理的实际风速和鼓风动能、缓解焦炭在高温区的粉化等措施,有效地改善了高炉的顺行状况,并逐步恢复高炉指标。  相似文献   
25.
The requirements on an object-oriented DBMS for management of information in a large, complex enterprise are presented. These requirements aid in the achievement of an environment characterized by data sharing, open architectures, application and data portability, and assurance of data integrity. They were defined from the point of view of a user of the DBMS; therefore they describe the expected functionality of the DBMS and do not specify the method of implementation to achieve this functionality. They encompass requirements on the data model, query and data manipulation languages, the system architecure, interfaces to the system, change management, and transaction management.  相似文献   
26.
Good methods are needed to specify, test, and debug material-handling control logic. This article surveys a number of representative methods for defining and describing control algorithms for programmable material-handling equipment used in flexible manufacturing systems. The methods are evaluated with regard to their suitability for communication between people and as bases for interfaces to automatic program generators. It is concluded that no single method is entirely satisfactory. Three methods (position diagrams, function block diagrams, and operation networks) have potential to be combined into an effective hybrid approach that minimizes the need for the user to switch between various conceptual models.  相似文献   
27.
28.
在役超高压水晶釜主要检测方法   总被引:1,自引:0,他引:1  
介绍了在役超高压水晶釜的常见缺陷以及应用超声波探伤、磁粉探伤、金相分析等无损检测方法对其进行在役检验的要点.  相似文献   
29.
This paper examines Total Quality Management (TQM) as defined by Dr. W. Edwards Deming including Deming's fourteen points and explains how the United States' Department of Defense (DOD) defines TQM and why TQM is necessary. It also covers how the DOD is planning on implementing TQM and the policy that has been established as guidance in the implementation process.  相似文献   
30.
This paper assesses the impacts of a GTL plant on the expansion of Brazil's oil refining segment. The GTL plant (50,000 bpd) was sized to start up operations in 2015, producing diesel and naphtha through the indirect route (FT-synthesis). This plant will consume the non-associated natural gas production from the recent discoveries at the Santos Basin (around 419 Bm3), and the associated gas production from the Campos Basin. Both basins are located in the Southeast of Brazil, the most populated, rich and industrialized region of the country. Two different criteria for refinery expansion were simulated in order to meet oil product demand scenarios. Findings show that depending on the refinery expansion criteria considered GTL will play a fundamental hole to meet the oil product demand forecast to Brazil in the next 10 years.  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