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   5220篇
  免费   205篇
  国内免费   83篇
电工技术   153篇
技术理论   3篇
综合类   256篇
化学工业   536篇
金属工艺   248篇
机械仪表   368篇
建筑科学   1511篇
矿业工程   258篇
能源动力   271篇
轻工业   167篇
水利工程   91篇
石油天然气   111篇
武器工业   14篇
无线电   146篇
一般工业技术   267篇
冶金工业   161篇
原子能技术   42篇
自动化技术   905篇
  2024年   11篇
  2023年   90篇
  2022年   127篇
  2021年   159篇
  2020年   163篇
  2019年   124篇
  2018年   91篇
  2017年   103篇
  2016年   162篇
  2015年   155篇
  2014年   333篇
  2013年   264篇
  2012年   366篇
  2011年   377篇
  2010年   246篇
  2009年   265篇
  2008年   239篇
  2007年   341篇
  2006年   320篇
  2005年   262篇
  2004年   210篇
  2003年   196篇
  2002年   144篇
  2001年   103篇
  2000年   94篇
  1999年   115篇
  1998年   83篇
  1997年   63篇
  1996年   42篇
  1995年   46篇
  1994年   30篇
  1993年   26篇
  1992年   23篇
  1991年   15篇
  1990年   14篇
  1989年   9篇
  1988年   8篇
  1987年   7篇
  1986年   9篇
  1985年   9篇
  1984年   9篇
  1983年   8篇
  1982年   9篇
  1981年   16篇
  1980年   5篇
  1979年   4篇
  1978年   3篇
  1977年   2篇
  1976年   2篇
  1960年   2篇
排序方式: 共有5508条查询结果,搜索用时 15 毫秒
1.
‘Renewable energy is an essential part of our strategy of decarbonization, decentralization, as well as digitalization of energy.’ – Isabelle Kocher.Current climate, health and economic condition of our globe demands the use of renewable energy and the development of novel materials for the efficient generation, storage and transportation of renewable energy. Hydrogen has been recognised as one of the most prominent carriers and green energy source with challenging storage, enabling decarbonization. Photocatalytic H2 (green hydrogen) production processes are targeting the intensification of separated solar energy harvesting, storage and electrolysis, conventionally yielding O2/H2. While catalysis is being investigated extensively, little is done on bridging the gap, related to reactor unit design, optimisation and scaling, be it that of material or of operation. Herein, metals, oxides, perovskites, nitrides, carbides, sulphides, phosphides, 2D structures and heterojunctions are compared in terms of parameters, allowing for efficiency, thermodynamics or kinetics structure–activity relationships, such as the solar-to-hydrogen (STH). Moreover, prominent pilot systems are presented summarily.  相似文献   
2.
《Oil and Energy Trends》2020,45(1):56-58
Currency exchanges rates – updated monthly. Economic indicators of industrial production. Countries included: France, Germany, Italy, the United Kingdom, the United States, Canada, Japan (Total G-7), Eurozone and Total EU-28 (Total OECD). Updated monthly. Economic indicators of car registration in the United States, Canada, France, Germany, Italy, Poland, Spain, Turkey, the United Kingdom, Japan, Republic of Korea and Other OECD (Total OECD-30). Updated monthly. Monthly averages of crude steel production in thousand metric tons for the United States, Canada, Brazil, Mexico, Austria, Belgium, Czech Republic, France, Germany, Italy, Netherlands, Poland, Spain, Sweden, Turkey, the United Kingdom, Russia, Ukraine, South Africa, Iran, China, India, Japan, Republic of Korea, Taiwan and Australia.  相似文献   
3.
《Oil and Energy Trends》2020,45(5):56-58
Currency exchanges rates – updated monthly. Economic indicators of industrial production. Countries included: France, Germany, Italy, the United Kingdom, the United States, Canada, Japan (Total G-7), Eurozone and Total EU-28 (Total OECD). Updated monthly. Economic indicators of car registration in the United States, Canada, France, Germany, Italy, Poland, Spain, Turkey, the United Kingdom, Japan, Republic of Korea and Other OECD (Total OECD-30). Updated monthly. Monthly averages of crude steel production in thousand metric tons for the United States, Canada, Brazil, Mexico, Austria, Belgium, Czech Republic, France, Germany, Italy, Netherlands, Poland, Spain, Sweden, Turkey, the United Kingdom, Russia, Ukraine, South Africa, Iran, China, India, Japan, Republic of Korea, Taiwan and Australia.  相似文献   
4.
Specialized varieties of sugar beets (Beta vulgaris L.) may be an eligible feedstock for advanced biofuel designation under the USA Energy Independence and Security Act of 2007. These non-food industrial beets could double ethanol production per hectare compared to alternative feedstocks. A mixed-integer mathematical programming model was constructed to determine the breakeven price of ethanol produced from industrial beets, and to determine the optimal size and biorefinery location. The model, based on limited field data, evaluates Southern Plains beet production in a 3-year crop rotation, and beet harvest, transportation, and processing. The optimal strategy depends critically on several assumptions including a just-in-time harvest and delivery system that remains to be tested in field trials. Based on a wet beet to ethanol conversion rate of 110 dm3 Mg−1 and capital cost of 128 M$ for a 152 dam3 y−1 biorefinery, the estimated breakeven ethanol price was 507 $ m−3. The average breakeven production cost of corn (Zea mays L.) grain ethanol ranged from 430 to 552 $ m−3 based on average net corn feedstock cost of 254 and 396 $ m−3 in 2014 and 2013, respectively. The estimated net beet ethanol delivered cost of 207 $ m−3 was lower than the average net corn feedstock cost of 254–396$ m−3 in 2013 and 2014. If for a mature industry, the cost to process beets was equal to the cost to process corn, the beet breakeven ethanol price would be $387 m-3 (587 $ m−3 gasoline equivalent).  相似文献   
5.
社会经济快速发展,科学技术不断进步,针对我国现代工业化工行业发展,所产生的新型化工技术应用,促进我国化工生产效率的提升。工业的发展不可避免地会带来污染物的产生,如果不能有效控制化工排放污染物,温室效应问题会更加严重。本文对绿色化工技术在精细化工中的有效应用进行研究,降低工业废气污染物排放量,维护生态环境平衡。  相似文献   
6.
7.
《Oil and Energy Trends》2019,44(8):58-60
Currency exchanges rates – updated monthly. Economic indicators of industrial production. Countries included: France, Germany, Italy, the United Kingdom, the United States, Canada, Japan (Total G-7), Eurozone and Total EU-28 (Total OECD). Updated monthly. Economic indicators of car registration in the United States, Canada, France, Germany, Italy, Poland, Spain, Turkey, the United Kingdom, Japan, Republic of Korea and Other OECD (Total OECD-30). Updated monthly. Monthly averages of crude steel production in thousand metric tons for the United States, Canada, Brazil, Mexico, Austria, Belgium, Czech Republic, France, Germany, Italy, Netherlands, Poland, Spain, Sweden, Turkey, the United Kingdom, Russia, Ukraine, South Africa, Iran, China, India, Japan, Republic of Korea, Taiwan and Australia.  相似文献   
8.
9.
吴江  万然  张志华 《包装工程》2003,24(6):99-101
阐述了可持续发展战略思想的重要意义和实施可持续设计的必要性,明确了工业设计师在整体设计流程中追求的终极目标。  相似文献   
10.
虚拟仪器(VI)将计算机采集测试分析引入到电子测量领域,用数字化和软件技术极大地提高了测量的灵活性。而VI远程测控系统是网络技术、通信技术一计算机虚拟技术结合的产物。远程控制技术能够使操作突破地域的限制,已在网络环境下PⅢ工控机上实现。  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