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   1361篇
  免费   54篇
  国内免费   7篇
电工技术   13篇
综合类   3篇
化学工业   279篇
金属工艺   18篇
机械仪表   23篇
建筑科学   88篇
矿业工程   4篇
能源动力   23篇
轻工业   161篇
水利工程   28篇
石油天然气   4篇
无线电   95篇
一般工业技术   140篇
冶金工业   335篇
原子能技术   23篇
自动化技术   185篇
  2021年   11篇
  2020年   15篇
  2019年   27篇
  2018年   31篇
  2017年   24篇
  2016年   30篇
  2015年   16篇
  2014年   29篇
  2013年   85篇
  2012年   35篇
  2011年   55篇
  2010年   49篇
  2009年   33篇
  2008年   54篇
  2007年   43篇
  2006年   48篇
  2005年   42篇
  2004年   36篇
  2003年   37篇
  2002年   34篇
  2001年   33篇
  2000年   28篇
  1999年   32篇
  1998年   89篇
  1997年   77篇
  1996年   49篇
  1995年   29篇
  1994年   24篇
  1993年   20篇
  1992年   20篇
  1991年   16篇
  1990年   13篇
  1989年   11篇
  1988年   17篇
  1987年   12篇
  1986年   17篇
  1985年   21篇
  1984年   11篇
  1983年   6篇
  1979年   6篇
  1978年   10篇
  1977年   5篇
  1976年   24篇
  1975年   6篇
  1974年   11篇
  1973年   12篇
  1971年   6篇
  1968年   6篇
  1966年   7篇
  1954年   6篇
排序方式: 共有1422条查询结果,搜索用时 31 毫秒
41.
Metallurgical and Materials Transactions B - Quantification of metal droplets ejected due to impinging gas jet on the surface of liquid metal is an important parameter for the understanding and for...  相似文献   
42.
Buying Power     
The global push toward finalizing and implementing the next generation of connected smart machinery—the Industry 4.0 protocols—begs the question: how will these new standards influence equipment purchasing decisions for plastics manufacturers?  相似文献   
43.
44.
Indigenous community members along the Slave River in Canada have voiced their concerns for the health of ecosystems under pressure from resource extraction, hydroelectric development and global climate change. We present a test case of traditional knowledge and scientific results about the spawning and migration patterns of fish in the Slave River and Delta. This dual knowledge system approach elucidates the broader connectivity of local study regions and can improve monitoring programmes by extending beyond the usual context/confines of the present or recent past, increasing the spatial and temporal range of system information.  相似文献   
45.
46.
Hazard mapping is essential to effective driver-vehicle interface (DVI) design. Determining which modality to use for situations of different criticality requires an understanding of the relative impact of signal parameters within each modality on perceptions of urgency and annoyance. Towards this goal we obtained psychometric functions for visual, auditory and tactile interpulse interval (IPI), visual color, signal word, and auditory fundamental frequency on perceptions of urgency, annoyance, and acceptability. Results indicate that manipulation of IPI in the tactile modality, relative to visual and auditory, has greater utility (greater impact on urgency than annoyance). Manipulations of color were generally rated as less annoying and more acceptable than auditory and tactile stimuli; but they were also rated as lower in urgency relative to other modality manipulations. Manipulation of auditory fundamental frequency resulted in high ratings of both urgency and annoyance. Results of the current investigation can be used to guide DVI design and evaluation.  相似文献   
47.
48.
Packaging fresh lamb in a vacuum (VAC) versus a 100% CO2 modified atmosphere (MAP) may influence product shelf-life and the bacterial communities. While VAC is a common packing method and 100% CO2 MAP is used in some countries, there is little information about how these different techniques affect the growth of spoilage bacteria and sensory attributes of lamb. The aim of this study was to assess changes in microbiological and organoleptic properties, and determine differences in microbial communities by terminal restriction fragment length polymorphism (TRFLP) and 454 pyrosequencing, in bone-in (BI) and bone-out (BO) MAP- and VAC-packed lamb shoulders stored at −0.3 °C over 12 wk. VAC and MAP lamb shoulders were acceptable in sensory test scores over 12 wk of storage at −0.3 °C, despite total viable count (TVC) and lactic acid bacteria (LAB) levels increasing to 8 log10 CFU/cm2 for VAC lamb and 4–6 log10 CFU/cm2 for MAP lamb. Similar to the sensory results, there were no significant differences in microbial communities between BI and BO product. However, types of bacteria were different between VAC and MAP packaging. Specifically, while VAC shoulder became dominated by Carnobacterium spp. in the middle of the storage period, the MAP shoulder microbial population remained similar from the start until later storage times.  相似文献   
49.
50.
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