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   11087篇
  免费   267篇
  国内免费   13篇
电工技术   138篇
综合类   7篇
化学工业   1776篇
金属工艺   173篇
机械仪表   221篇
建筑科学   512篇
矿业工程   17篇
能源动力   277篇
轻工业   753篇
水利工程   80篇
石油天然气   138篇
武器工业   1篇
无线电   921篇
一般工业技术   1690篇
冶金工业   3240篇
原子能技术   126篇
自动化技术   1297篇
  2021年   122篇
  2020年   100篇
  2019年   114篇
  2018年   121篇
  2017年   115篇
  2016年   129篇
  2015年   124篇
  2014年   163篇
  2013年   559篇
  2012年   299篇
  2011年   404篇
  2010年   305篇
  2009年   302篇
  2008年   405篇
  2007年   390篇
  2006年   336篇
  2005年   323篇
  2004年   283篇
  2003年   267篇
  2002年   312篇
  2001年   203篇
  2000年   206篇
  1999年   268篇
  1998年   598篇
  1997年   438篇
  1996年   351篇
  1995年   216篇
  1994年   204篇
  1993年   225篇
  1992年   148篇
  1991年   137篇
  1990年   127篇
  1989年   155篇
  1988年   160篇
  1987年   133篇
  1986年   130篇
  1985年   163篇
  1984年   187篇
  1983年   132篇
  1982年   122篇
  1981年   141篇
  1980年   118篇
  1979年   151篇
  1978年   119篇
  1977年   161篇
  1976年   198篇
  1975年   94篇
  1974年   101篇
  1973年   114篇
  1972年   82篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
Abstract

Industry 4.0 aims at providing a digital representation of a production landscape, but the challenges in building, maintaining, optimizing, and evolving digital models in inter-organizational production chains have not been identified yet in a systematic manner. In this paper, various Industry 4.0 research and technical challenges are addressed, and their present scenario is discussed. Moreover, in this article, the novel concept of developing experience-based virtual models of engineering entities, process, and the factory is presented. These models of production units, processes, and procedures are accomplished by virtual engineering object (VEO), virtual engineering process (VEP), and virtual engineering factory (VEF), using the knowledge representation technique of Decisional DNA. This blend of the virtual and physical domains permits monitoring of systems and analysis of data to foresee problems before they occur, develop new opportunities, prevent downtime, and even plan for the future by using simulations. Furthermore, the proposed virtual model concept not only has the capability of Query Processing and Data Integration for Industrial Data but also real-time visualization of data stream processing.  相似文献   
2.
We investigate the challenges of building an end-to-end cloud pipeline for real-time intelligent visual inspection system for use in automotive manufacturing. Current methods of visual detection in automotive assembly are highly labor intensive, and thus prone to errors. An automated process is sought that can operate within the real-time constraints of the assembly line and can reduce errors. Components of the cloud pipeline include capture of a large set of high-definition images from a camera setup at the assembly location, transfer and storage of the images as needed, execution of object detection, and notification to a human operator when a fault is detected. The end-to-end execution must complete within a fixed time frame before the next car arrives in the assembly line. In this article, we report the design, development, and experimental evaluation of the tradeoffs of performance, accuracy, and scalability for a cloud system.  相似文献   
3.
4.
5.
6.
7.
Passive permeability is a key property in drug disposition and delivery. It is critical for gastrointestinal absorption, brain penetration, renal reabsorption, defining clearance mechanisms and drug-drug interactions. Passive diffusion rate is translatable across tissues and animal species, while the extent of absorption is dependent on drug properties, as well as in vivo physiology/pathophysiology. Design principles have been developed to guide medicinal chemistry to enhance absorption, which combine the balance of aqueous solubility, permeability and the sometimes unfavorable compound characteristic demanded by the target. Permeability assays have been implemented that enable rapid development of structure-permeability relationships for absorption improvement. Future advances in assay development to reduce nonspecific binding and improve mass balance will enable more accurately measurement of passive permeability. Design principles that integrate potency, selectivity, passive permeability and other ADMET properties facilitate rapid advancement of successful drug candidates to patients.  相似文献   
8.
9.
We analyze travel times for automated storage/retrieval systems. In particular, we apply our travel time model to turnover-based storage systems and determine the mean and variance of dual command travel times. We present detailed numerical results for selected rack shape factors and ABC inventory profiles. We then investigate the effect of alternative rack configurations on travel time performance measures. We also show how to determine the throughput of miniload systems with turnover-based storage and exponentially distributed pick times.  相似文献   
10.
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