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   12655篇
  免费   477篇
  国内免费   309篇
电工技术   185篇
综合类   419篇
化学工业   2677篇
金属工艺   919篇
机械仪表   1289篇
建筑科学   591篇
矿业工程   473篇
能源动力   565篇
轻工业   529篇
水利工程   90篇
石油天然气   238篇
武器工业   48篇
无线电   763篇
一般工业技术   1153篇
冶金工业   593篇
原子能技术   112篇
自动化技术   2797篇
  2024年   18篇
  2023年   83篇
  2022年   125篇
  2021年   220篇
  2020年   245篇
  2019年   201篇
  2018年   158篇
  2017年   228篇
  2016年   335篇
  2015年   360篇
  2014年   637篇
  2013年   798篇
  2012年   635篇
  2011年   992篇
  2010年   616篇
  2009年   657篇
  2008年   581篇
  2007年   758篇
  2006年   749篇
  2005年   724篇
  2004年   664篇
  2003年   602篇
  2002年   523篇
  2001年   416篇
  2000年   376篇
  1999年   306篇
  1998年   273篇
  1997年   217篇
  1996年   180篇
  1995年   157篇
  1994年   160篇
  1993年   92篇
  1992年   73篇
  1991年   62篇
  1990年   47篇
  1989年   30篇
  1988年   33篇
  1987年   15篇
  1986年   12篇
  1985年   12篇
  1984年   18篇
  1983年   9篇
  1982年   10篇
  1981年   14篇
  1980年   2篇
  1979年   3篇
  1978年   3篇
  1977年   5篇
  1974年   3篇
  1971年   1篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
951.
基于层次分析法的车炮匹配性评价   总被引:1,自引:0,他引:1  
基于层次分析法的车炮匹配性评价体系分为目标层、准则层和方案层.目标层用于确定系统固有综合性能及要求.准则层由若干相关评价因素组成,是同类因素综合形成的评价指标.方案层负责衡量或描述系统特定性能的基本参数.该体系以某型坦克为例,采用和积法进行层次单排序,计算出评价因素的权重向量,以确定准则层对目标层的权重向量.  相似文献   
952.
Detailed, high‐resolution numerical simulations have been performed of the buoyancy‐driven motion of deformable, chemically reacting bubble and droplet swarms. Mass transfer rates and chemical reaction selectivities were determined and a comparison is presented between the results for bubble/droplet swarms and single bubbles. The mixing in the wake of bubbles was characterized as well. It was shown that for mixing‐sensitive reaction networks, the hydrodynamics of the bubble swarm may significantly impact the reaction selectivity. Four special cases are highlighted, i.e., highly exothermic reactions, heterogeneously catalyzed reactions, animal cell cultures and experiments. The most important outcome of this work is that bubble swarms and the impact of the swarm hydrodynamics on reacting systems can be studied in detail. This is the first study of this kind reported in the literature. Its importance is paramount as knowledge of the unique flow dynamics inside bubble swarms is crucial to understanding the mechanisms controlling mass transport and chemical reactions and is a prerequisite for effective process intensification.  相似文献   
953.
Integration of Product Design and Assembly Planning in the Digital Factory   总被引:1,自引:0,他引:1  
H. Bley  C. Franke 《CIRP Annals》2004,53(1):25-30
As assembly process planning fulfils the main function of connecting product design to production simulation and thus, the production system itself, a feasible software solution is needed to support this process. Thus, a novel concept is presented that aims at improving the integration of digital product design and assembly planning by introducing a consistent data structuring. This approach helps to reduce redundant tasks and supports the continuous data exchange. It is based on the use of assembly features, i.e. pre-defined geometry elements that contain additional technological information.The prototypical implementation of the concept focuses on the use of commercially available software tools, expanding them with additional functionality for the application of assembly features. The feature-based concept has been tested with a scenario from the automotive supplier industry. For the considered assembly, a comparison between the conventional and the feature-based planning approach is presented in the paper. It points out that the major advantages of the developed concept can be seen in an improved data consistency as well as a higher level of efficiency within the planning activities.  相似文献   
954.
近年高速工具钢的发展概况   总被引:12,自引:1,他引:11  
罗迪  李忠之 《特殊钢》1996,17(2):8-14
概述了高速工具钢钢种、工艺和基础研究的近期发展;并叙述了低合金高速钢、粉末高速钢以及高速钢表面热处理的发展动态。  相似文献   
955.
Along with the explosive increase of product data management systems (PDMs),integrating polymorphic PDMs is becoming one of the focuses in the field. Aner brief describing several features of PDM, and market requirements and required performance for integrating the polymorphic PDMs, the paper specializes in discussing some key technologies involved in virtual enterprise oriented integrated development. Some implementing strategies and procedures are proposed.  相似文献   
956.
蔡廷书 《宽厚板》1998,4(4):1-6
本文综述了炉外精炼工艺技术的进步、应用及优缺点。  相似文献   
957.
A crucial step in any system design concerns the allocation of functions between human and machine. In simultaneous engineering, function allocation is potentially an issue both in product design — if the product is a technical system itself — and in process design. It is argued that well-founded function allocation decisions in relation to the production process are of particular importance in simultaneous engineering as less and less time is allowed for compensation for inadequate or missing decisions which will impede production effectiveness. The focus of recent methods for the allocation of functions is to operationalize the concept of complementarity, meaning to provide guidelines for complementing humans by technical systems instead of replacing them gradually as technical systems become more and more sophisticated. As systems design becomes more complex, involving more and faster changes and placing higher demands on engineers as well as system operators, the idea of complementary gains importance because it stresses the need to allocate functions in a way that supports human control over the production process and the development and maintenance of the necessary skills. Looking at existing methods and instruments for the complementary allocation of functions, one is at first sight confronted with a multitude of criteria for complementarity, but to date neither a fixed set of criteria, comparable to software usability criteria, nor widely accepted methods for their measurement exist. As part of a research project concerned with the development of guidelines whose objective is to assist engineers in designing work systems according to the complementarity principle, four central criteria for complementary function allocation were identified: dynamic coupling, process transparency, human decision authority, and flexibility. These criteria and their application in a design process are illustrated by means of a case study and discussed in terms of other approaches to complementary design as well as their use for simultaneous engineering projects.

Relevance to industry

Adequate allocation of functions between human and machine is crucial for the effectiveness of any production system. With more complex and faster design processes in simultaneous engineering projects, the need for methods supporting prospective analysis and design of human-machine systems has increased even more. The article presents such a method based on the principle of complementarity between human operator and technical system and illustrates its use by means of a case study.  相似文献   

958.
本文介绍了利用VAX─11机上修补实用程序PATCH修改映象文件和外部处理程序相结合剖析软件的两种实用有效的方法。一种为将中间信息写入外部文件的静态法,一种为利用父子进程通讯输出中间信息的动态法。  相似文献   
959.
梁睦 《机械制造》1996,(6):19-20
介绍了采用定、滑尺机构重复定位与分段冲孔的工艺,解决长板冲孔加工,中小批量和短期大批量生产的关键问题。  相似文献   
960.
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