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   1095篇
  免费   35篇
  国内免费   3篇
电工技术   21篇
综合类   1篇
化学工业   242篇
金属工艺   32篇
机械仪表   31篇
建筑科学   20篇
矿业工程   5篇
能源动力   53篇
轻工业   78篇
水利工程   8篇
石油天然气   2篇
无线电   84篇
一般工业技术   283篇
冶金工业   127篇
原子能技术   5篇
自动化技术   141篇
  2024年   4篇
  2023年   12篇
  2022年   28篇
  2021年   48篇
  2020年   48篇
  2019年   43篇
  2018年   45篇
  2017年   43篇
  2016年   28篇
  2015年   31篇
  2014年   42篇
  2013年   77篇
  2012年   36篇
  2011年   53篇
  2010年   53篇
  2009年   54篇
  2008年   41篇
  2007年   32篇
  2006年   22篇
  2005年   23篇
  2004年   12篇
  2003年   18篇
  2002年   22篇
  2001年   14篇
  2000年   12篇
  1999年   11篇
  1998年   37篇
  1997年   23篇
  1996年   17篇
  1995年   8篇
  1994年   9篇
  1993年   16篇
  1992年   7篇
  1990年   10篇
  1989年   10篇
  1988年   9篇
  1987年   10篇
  1986年   7篇
  1985年   20篇
  1984年   10篇
  1983年   9篇
  1982年   9篇
  1981年   10篇
  1980年   15篇
  1979年   9篇
  1977年   3篇
  1976年   11篇
  1975年   3篇
  1974年   4篇
  1966年   2篇
排序方式: 共有1133条查询结果,搜索用时 0 毫秒
131.
132.
133.
Kumar  Munish  Nath  Vandana 《Wireless Networks》2020,26(7):5485-5499
Wireless Networks - This paper outlines a simple design of a compact wideband microstrip-line fed antenna having two rotated elliptical wide-slots (EWSs). Here, both the elliptical wide-slots are...  相似文献   
134.
Linz-Donawitz(LD) slag Geopolymer(LDSGP), a porous aluminosillicate geopolymeric adsorbent, has been synthesized from steel plant LD slag for efficient removal of Zinc(II) ions from wastewater, thus presenting a solution for converting industrial waste to adsorbent for wastewater treatment. The colloid paste of raw LD slag and the alkaline activator (10?M NaOH?+?sodium silicate (1:1 w/w)) has been cured for 3?days at low temperature to geopolymerize the calcium oxide rich LD slag. The BET surface area of LDSGP adsorbent (30.84?m2/g) has improved considerably compared to raw LDS (4.85?m2/g) and the FESEM and HRTEM images reveal the presence of micropetal and cauliflower like structures at outer surface of the adsorbent particles. The mesoporous nature of LDSGP adsorbent can be understood by analyzing N2 adsorption-desorption and pore size distribution plot. The PXRD pattern of LDSGP adsorbent powder confirms the presence of Ca2SiO4 and Ca3SiO5 in the geopolymeric matrix. Langmuir isotherm model correlates the batch adsorption data of Zn2+ ions onto LDSGP particles at 298?K, 308?K and 318?K. The maximum Zn2+ ions adsorption capacity of LDSGP is 86?mg/g at 318?K. The adsorption kinetic data is correlated with pseudo-second-order model indicating chemisorption of Zn2+ ions onto LD slag geopolymeric powder adsorbent.  相似文献   
135.
Migration tests at different temperatures and storage periods were performed to evaluate the release of active compounds from active whey protein films (WPFs) to a food and food simulants. Whey protein film incorporated with different levels of an optimized essential oils (EOs) blend (1%, 2%, 2.7%, and 5%, w/w) were prepared by casting. This blend contained EOs from rosemary and 2 species of cinnamon. Salami was packaged with WPF and stored during 180 days at 5°C. Temperature influenced significantly the migration of compounds (P<.1). It was observed that eucalyptol was the compound that presented the highest potential of migration into 95% ethanol (v/v). After contact of film with salami, it was observed that, in general, more than 50% of active compounds released from WPF to salami. It was observed that higher amounts of active compounds were released to salami than to fatty food simulant. Results suggested that the release of compounds depends on their affinity with the food/food simulant, temperature, their concentration in packaging, and composition of food. Active packaging may ensure the quality of food due the migration of compounds from EO with antimicrobial and antioxidant activity incorporated in the film to the foodstuff.  相似文献   
136.
137.
138.
Journal of Materials Science - Palladium–bismuth oxoiodide nanocomposites of various molar ratios of Pd and BiOI have been synthesized by the facile solvothermal method following the chemical...  相似文献   
139.
Fly ash is milled for 0, 30 and 90?min and used to study the role of particle size on the kinetics of geopolymer formation. The increase in particle fineness is very prominent in the initial milling stage, and then slows down due to agglomeration effect of finer fraction. The fly ash geopolymerization kinetics and its mechanism is determined using heat of reaction data measured by isothermal conduction calorimeter. The improvement in reaction rate with milling is correlated with the median particle size of the fly ash. The apparent activation energy decreases with size reduction because finer fractions are more prone to alkali activation. Although the kinetics changes with particle fineness, but no alternation is detected in the reaction mechanism, governed by nucleation and growth. The apparent activation energy evaluated by rate method is showing three major steps of geopolymerization such as dissolution, gel formation and restructuring.  相似文献   
140.
Nath  Rajakishore  Sahu  Vineet 《AI & Society》2020,35(1):103-111
AI & SOCIETY - The advent of the intelligent robot has occupied a significant position in society over the past decades and has given rise to new issues in society. As we know, the primary aim...  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