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   530篇
  免费   23篇
  国内免费   1篇
电工技术   8篇
综合类   2篇
化学工业   161篇
金属工艺   8篇
机械仪表   14篇
建筑科学   13篇
能源动力   26篇
轻工业   42篇
水利工程   8篇
石油天然气   4篇
无线电   28篇
一般工业技术   116篇
冶金工业   16篇
自动化技术   108篇
  2024年   3篇
  2023年   14篇
  2022年   21篇
  2021年   39篇
  2020年   17篇
  2019年   16篇
  2018年   20篇
  2017年   23篇
  2016年   33篇
  2015年   21篇
  2014年   17篇
  2013年   48篇
  2012年   30篇
  2011年   31篇
  2010年   20篇
  2009年   38篇
  2008年   24篇
  2007年   19篇
  2006年   17篇
  2005年   9篇
  2004年   11篇
  2003年   3篇
  2002年   13篇
  2001年   9篇
  2000年   8篇
  1999年   9篇
  1998年   11篇
  1997年   6篇
  1996年   6篇
  1995年   1篇
  1994年   1篇
  1991年   2篇
  1989年   1篇
  1988年   1篇
  1987年   2篇
  1986年   1篇
  1984年   1篇
  1983年   1篇
  1982年   1篇
  1980年   2篇
  1979年   2篇
  1977年   2篇
排序方式: 共有554条查询结果,搜索用时 0 毫秒
551.
Silicon - In this paper, we propose dual material gate with dual-k dielectric gate oxide double gate junctionless transistor ‘DMG-DK-JLT’ for significant enhancement of performance. We...  相似文献   
552.
This paper is devoted to the investigation of feedback stabilization of affine control systems on real Banach spaces. Under an appropriate decomposition of the state space, we provide sufficient conditions for exponential stabilization of the system at hand. Furthermore, we show that the proposed feedback law remains a stabilizing control under some types of perturbations on the dynamic and the control operator. Finally, two illustrative examples are provided.  相似文献   
553.
The fabrication of low-cost, effective, and highly integrated nanostructured materials through simple and reproducible methods for high-energy-density supercapacitors is highly desirable. Herein, an activated carbon cloth (ACC) is designed as the functional scaffold for supercapacitors and treated hydrothermally to deposit NiCo nanoneedles working as internal core, followed by a dip-dry coating of NiOOH nanoflakes core–shell and uniform hydrothermal deposition of CoMoO4 nanosheets serving as an external shell. The structured core–shell heterostructure ACC@NiCo@NiOOH@CoMoO4 electrode resulted in exceptional specific areal capacitance of 2920 mF cm−2 and exceptional cycling stability for 10 000 cycles. Moreover, the fabricated electrode is developed into an asymmetric supercapacitor which demonstrates excellent areal capacitance, energy density, and power density within the broad potential window of 1.7 V with a cycling life of 92.4% after 10 000 charge–discharge cycles, which reflects excellent cycle life. The distinctive core–shell structure, highly conductive substrate, and synergetic effect of coated material results in more electrochemical active sites and flanges for effective electrons and ion transportation. This unique technique provides a new perspective for cost-efficient supercapacitor applications.  相似文献   
554.
The cross-flow heat exchanger involves a tractor moving between two fluids that flow in a direction perpendicular to each other, and one of the fluids is often a liquid and the other is a gas. This type of heat exchanger has been studied in many previous studies for its importance in air conditioning applications and many industrial applications. In this type of heat exchanger, the surface area for heat transfer is very large. Therefore, many techniques have been used to improve the thermal and dynamic performance of this type of heat exchanger. In this study, previous studies that used metallic foam as one of the ways to improve the performance of heat exchangers were reviewed. The most important techniques that were used in previous studies during the process of evaluating the thermal performance of a cross-flow heat exchanger in the presence of different types of metal foam were clarified. The use of metal foam depends on important factors, including (1) the type of material, where copper and aluminum were used in most of the previous studies, due to their availability and ease of foam formation using these materials, in addition to the good thermal properties, (2) porosity, where the porosity value of metal foam ranged between 0.85 and 0.98 in the previous studies, (3) the density of pores, most of the studies ranged between 10 and 40 PPI.  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