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   141881篇
  免费   21054篇
  国内免费   4325篇
电工技术   7307篇
技术理论   4篇
综合类   7557篇
化学工业   37686篇
金属工艺   6182篇
机械仪表   6991篇
建筑科学   9004篇
矿业工程   3007篇
能源动力   3175篇
轻工业   15447篇
水利工程   2263篇
石油天然气   4992篇
武器工业   865篇
无线电   16112篇
一般工业技术   22963篇
冶金工业   4601篇
原子能技术   1035篇
自动化技术   18069篇
  2024年   314篇
  2023年   1759篇
  2022年   2777篇
  2021年   4284篇
  2020年   4649篇
  2019年   5710篇
  2018年   5671篇
  2017年   6240篇
  2016年   6588篇
  2015年   8080篇
  2014年   9019篇
  2013年   11421篇
  2012年   9214篇
  2011年   9376篇
  2010年   9258篇
  2009年   9064篇
  2008年   7992篇
  2007年   7603篇
  2006年   7172篇
  2005年   5872篇
  2004年   4614篇
  2003年   4093篇
  2002年   4138篇
  2001年   3631篇
  2000年   2947篇
  1999年   2301篇
  1998年   1415篇
  1997年   1189篇
  1996年   1109篇
  1995年   949篇
  1994年   797篇
  1993年   689篇
  1992年   468篇
  1991年   375篇
  1990年   330篇
  1989年   330篇
  1988年   270篇
  1987年   241篇
  1986年   242篇
  1985年   206篇
  1984年   196篇
  1983年   204篇
  1982年   174篇
  1981年   218篇
  1980年   180篇
  1979年   179篇
  1975年   202篇
  1974年   188篇
  1973年   365篇
  1972年   212篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
Alpha Versionen sind Lehrbücher, Gesetze, Produkthochglanzprospekte, Aktienneuemissionsanzeigen, Regierungserklärungen. Dahinter ist das Reale. Hinter den Lehrbüchern die vorlesende Forscherpersönlichkeit, hinter dem Prospekt der Rat des erfahrenen Fachverkäufers. Alpha Versionen meiden Urteile, Meinungen und Leidenschaftlichkeit. Diese Kolumne ist kompromißlos beta.  相似文献   
63.
64.
65.
Discovering unknown adverse drug reactions (ADRs) in postmarketing surveillance as early as possible is highly desirable. Nevertheless, current postmarketing surveillance methods largely rely on spontaneous reports that suffer from serious underreporting, latency, and inconsistent reporting. Thus these methods are not ideal for rapidly identifying rare ADRs. The multiagent systems paradigm is an emerging and effective approach to tackling distributed problems, especially when data sources and knowledge are geographically located in different places and coordination and collaboration are necessary for decision making. In this article, we propose an active, multiagent framework for early detection of ADRs by utilizing electronic patient data distributed across many different sources and locations. In this framework, intelligent agents assist a team of experts based on the well‐known human decision‐making model called Recognition‐Primed Decision (RPD). We generalize the RPD model to a fuzzy RPD model and utilize fuzzy logic technology to not only represent, interpret, and compute imprecise and subjective cues that are commonly encountered in the ADR problem but also to retrieve prior experiences by evaluating the extent of matching between the current situation and a past experience. We describe our preliminary multiagent system design and illustrate its potential benefits for assisting expert teams in early detection of previously unknown ADRs. © 2007 Wiley Periodicals, Inc. Int J Int Syst 22: 827–845, 2007.  相似文献   
66.
介绍了天津钢铁工业结构调整改造后的新钢铁企业炼钢车间的自动控制系统,系统的配置、主要功能,并对系统做出评价。  相似文献   
67.
A novel strategy of sweep coagulation to treat low turbidity water is presented herein. Study findings demonstrated that an Na+‐saturated bentonite with medium cation exchange capacity (CEC) resulted in significant turbidity removal at a bentonite dosage of 30 mg dm?3. Bentonite dispersion with fully delaminated platelets tended to undergo a more porous type of coagulation with intense face‐to‐face interactions of platelets and effectively entrapped TiO2 particles in band‐type structures. This type of coagulation usually results in a large volume of settled flocs with a fluffy structure and excellent turbidity removal efficiency for sweep coagulation. The sign and magnitude of electrical charge on TiO2 particles has a minor effect on the efficiency of sweep coagulation. Copyright © 2005 Society of Chemical Industry  相似文献   
68.
Liquid–liquid two‐phase epoxidation from cyclohexene and cyclooctene in aqueous potassium peroxymonosulfate (commercially available as Oxone®) solution was studied as an application in pollution prevention. To avoid potential emissions of volatile organic compounds an aqueous solution was employed to replace the usual chlorinated solvents used in epoxide production. A droplet column reactor and stirred tank reactor were used to investigate two‐phase synthesis of epoxide. An aqueous Oxone® solution was used to oxidize a dispersion of alkene droplets and form epoxide. The study of aqueous epoxidation in both reactors showed that the epoxidation of alkenes can be represented as a first order reaction with respect to alkene. The salting out effect of Oxone® concentration was studied in both reactors and found to be very similar at optimal conditions. In comparing the two reactors, it was found that the droplet column reactor produces larger quantities of product per unit reactor volume for the same reaction time. The objective of this study is to provide an alternative reactor design and synthesis route that can meet pollution prevention goals. Copyright © 2004 Society of Chemical Industry  相似文献   
69.
70.
Design science in information systems research   总被引:1,自引:1,他引:0  
  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