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   886篇
  免费   48篇
电工技术   17篇
综合类   1篇
化学工业   211篇
金属工艺   14篇
机械仪表   16篇
建筑科学   34篇
矿业工程   7篇
能源动力   37篇
轻工业   30篇
水利工程   3篇
石油天然气   2篇
无线电   74篇
一般工业技术   235篇
冶金工业   67篇
原子能技术   4篇
自动化技术   182篇
  2023年   4篇
  2022年   10篇
  2021年   20篇
  2020年   14篇
  2019年   26篇
  2018年   24篇
  2017年   22篇
  2016年   29篇
  2015年   27篇
  2014年   27篇
  2013年   59篇
  2012年   40篇
  2011年   78篇
  2010年   53篇
  2009年   79篇
  2008年   42篇
  2007年   53篇
  2006年   52篇
  2005年   52篇
  2004年   38篇
  2003年   13篇
  2002年   29篇
  2001年   15篇
  2000年   11篇
  1999年   17篇
  1998年   14篇
  1997年   12篇
  1996年   8篇
  1995年   9篇
  1994年   5篇
  1993年   6篇
  1992年   3篇
  1991年   4篇
  1990年   3篇
  1988年   4篇
  1986年   2篇
  1985年   2篇
  1981年   2篇
  1980年   2篇
  1979年   2篇
  1978年   2篇
  1977年   3篇
  1975年   2篇
  1966年   2篇
  1961年   1篇
  1958年   1篇
  1957年   1篇
  1955年   1篇
  1943年   1篇
  1942年   1篇
排序方式: 共有934条查询结果,搜索用时 46 毫秒
931.
The relationships between protein content and quality and the loaf characteristics of hearth breads made from the respective flours were investigated for 20 wheat genotypes, comprising both commercially grown cultivars and advanced breeding lines, grown in 1997 and 1998. In both years the average protein content was increased by increasing the level of nitrogenous fertiliser application, this effect being more pronounced in 1997 than in 1998. Grain samples were milled and evaluated for endosperm hardness, protein content, SDS sedimentation volume, mixing properties and baking quality determined by a hearth bread baking test using optimal mixing and fixed proving time. When producing hearth bread, both the form (height/width) ratio and loaf volume are critical external characteristics. Genotype differences, mainly due to differences in protein quality, were more important for both form ratio and loaf volume than differences in protein content. The dough development time of the Farinograph, operated at high speed (126 rev min?1), was the best indicator of heart bread baking quality, giving high positive correlations to both the volume (r = 0.89) and form ratio of the loaf (r = 0.90). Climatic differences between the two years, in particular temperature during ripening, also affected the quality parameters studied. Copyright © 2004 Society of Chemical Industry  相似文献   
932.
Hot Isostatic Pressing (HIP) is a technology that has been around for 60+ years. By using high temperature and high gas pressure, dry metal and ceramic powders can be consolidated and a volume decrease can be achieved. Later developments include rapid cooling and rapid quenching to enable higher productivity and high-pressure heat treatment. This paper shows the advantages of having HIPing and Heat Treatment combined for Powder metallurgy parts.  相似文献   
933.
With the increasing demand for wind energy, it is important to be able to understand and predict the available wind resources. To that end, the present wind tunnel study addresses the flow in the induction and entrance region of wind farms through particle image velocimetry, with focus on differences between actuator disks and two-bladed rotating wind turbine models. Both staggered and aligned farm layouts are examined for three different incoming wind directions. For each layout, 69 disks or turbines are used, and the field of view ranges from 12 rotor diameters upstream of the farms to 8 diameters downstream of the first row. The results show that the induction, or blockage effect, is higher for the disks, even though the thrust (or drag) coefficient is the same. In contrast, the wake is stronger downstream of the turbines. The orientation and layout of the farm do not have a major impact on the results. Modal decomposition of the flow shows that the flow structure similarity between the disk and turbines improves downstream of the second row of wake generating objects, indicating that the substitution of wind turbines by actuator disks is more appropriate for wind farms than for the investigation of single wakes.  相似文献   
934.
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