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   300篇
  免费   16篇
电工技术   2篇
化学工业   77篇
机械仪表   1篇
建筑科学   18篇
能源动力   11篇
轻工业   50篇
水利工程   3篇
无线电   18篇
一般工业技术   47篇
冶金工业   38篇
自动化技术   51篇
  2024年   1篇
  2023年   3篇
  2022年   6篇
  2021年   13篇
  2020年   4篇
  2019年   13篇
  2018年   15篇
  2017年   6篇
  2016年   12篇
  2015年   11篇
  2014年   11篇
  2013年   17篇
  2012年   28篇
  2011年   21篇
  2010年   16篇
  2009年   10篇
  2008年   17篇
  2007年   13篇
  2006年   13篇
  2005年   10篇
  2004年   3篇
  2003年   5篇
  2002年   9篇
  2001年   2篇
  2000年   4篇
  1999年   5篇
  1998年   13篇
  1997年   10篇
  1996年   5篇
  1995年   2篇
  1994年   2篇
  1993年   1篇
  1992年   3篇
  1991年   1篇
  1989年   1篇
  1986年   1篇
  1985年   1篇
  1984年   1篇
  1983年   1篇
  1981年   1篇
  1978年   1篇
  1976年   1篇
  1975年   1篇
  1972年   2篇
排序方式: 共有316条查询结果,搜索用时 0 毫秒
311.
Bulletin of Engineering Geology and the Environment - Consideration of the effects of the site response in the design of civil structures systems is of important to mitigate the damages to a...  相似文献   
312.
313.
This paper presents a model (inspired by another model) to calculate water temperature in free-surface flow with two main innovations: the convective heat transfer occurs only at the wetted perimeter of pipes, and the model was integrated to commercial software used for hydraulic calculations in drainage systems. Given these innovations, we could reduce the number of modeling input data to calculate the temperature of water and soil in the radial and tangential directions along the pipes, with the advantages of using industry-standard software. To test the performance of the model, it was firstly calibrated in two sets of experiments (to calibrate the hydraulic and the thermal parameters separately), and benchmarked with a third controlled discharge against the case model. The results indicate that in unsteady-state situations the parsimonious model can be twice as accurate as the underlying model because the parsimonious model considers the hydraulic influence of sewer infrastructure.  相似文献   
314.
315.
Key variables in ecosystems tend to operate on widely different time‐scales. These time‐scales become relevant when a disturbance rocks the ecosystem. Here we try to explain the fast dynamics of plankton and nutrients in the water column of floodplain lakes after disturbances (inundations). We take advantage of natural experiments, that is occasional massive overflow of floodplain lakes with river water. We sampled 10 lakes in two floodplains along the Dutch river Waal monthly for 3 years, capturing the impact of three inundation events. The inundations reset the plankton as well as chemical composition of most lakes to largely the same state. While biologically inert macro‐ion data reflected a large and long lasting impact of the river water, dynamics of nutrients, phytoplankton and zooplankton communities between lakes diverged in a few weeks to regimes characteristic for the different lakes. While one spring inundation synchronized plankton dynamics to let the subsequent clear water phase occur at the same moment in different lakes, winter inundations did not have the same effect and apparently dynamics quickly diverged. Our results showed that effects of inundations and other processes that affect the state of the ecosystem should be studied considering the level of the slow components such as the sediment nutrient pool, fish stock and macrophyte communities. Plankton communities and lake water nutrient status give a practically instantaneous reflection of the condition of these slow components. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   
316.
The microstrocture of poly(butylene terephthalate) (PBT) has been investigated at the different stages of the manufacture of a new generation of composite materials, i.e., commingled Twintex® PBT/glass fiber composites. From differential scanning calorimetry and wide angle X‐ray scattering analysis in addition to density measurements and optical microscopy observations, it was concluded that the different stages of the composite manufacture induce some changes in the crystalline forms of PBT. In particular, the drawing of PBT can promote the formation of the β phase. The analysis of the crystallization kinetics points out the nucleation role played by the fibers. It is concluded that the growth of a transcrystalline region in the vicinity of fibers is promoted by the elevated pressure and temperature used in the manufacturing process of the composites.  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