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   1473篇
  免费   97篇
  国内免费   13篇
电工技术   35篇
综合类   7篇
化学工业   413篇
金属工艺   36篇
机械仪表   56篇
建筑科学   46篇
矿业工程   5篇
能源动力   122篇
轻工业   96篇
水利工程   31篇
石油天然气   20篇
无线电   126篇
一般工业技术   267篇
冶金工业   32篇
原子能技术   22篇
自动化技术   269篇
  2024年   7篇
  2023年   31篇
  2022年   46篇
  2021年   101篇
  2020年   69篇
  2019年   108篇
  2018年   116篇
  2017年   119篇
  2016年   99篇
  2015年   84篇
  2014年   70篇
  2013年   168篇
  2012年   113篇
  2011年   126篇
  2010年   64篇
  2009年   59篇
  2008年   48篇
  2007年   25篇
  2006年   18篇
  2005年   11篇
  2004年   8篇
  2003年   5篇
  2002年   5篇
  2001年   3篇
  2000年   5篇
  1999年   2篇
  1998年   6篇
  1997年   3篇
  1996年   4篇
  1995年   3篇
  1994年   4篇
  1993年   4篇
  1992年   1篇
  1991年   4篇
  1990年   2篇
  1989年   4篇
  1988年   1篇
  1987年   6篇
  1986年   4篇
  1985年   4篇
  1984年   2篇
  1983年   2篇
  1982年   4篇
  1981年   1篇
  1977年   5篇
  1976年   3篇
  1975年   1篇
  1974年   1篇
  1973年   2篇
  1972年   2篇
排序方式: 共有1583条查询结果,搜索用时 15 毫秒
71.
72.
Clean Technologies and Environmental Policy - In this study, aminolysis of polyester fabric was carried out along with in situ synthesis of silver nanoparticles in a single-step processing at room...  相似文献   
73.
Microsystem Technologies - This article presented a numerical method for discovering the free vibration of a spinning bi-dimensional functionally graded materials (FGM) micro circular plate exposed...  相似文献   
74.
75.
76.
Control charts are intended to aid quality practitioners in monitoring whether a change has occurred in a process. When a control chart indicates an out-of-control signal, it means that the process has changed. However, control chart signals do not indicate the real time of process changes; so estimators are applied to indicate the time when a change in the process takes place, which is referred to as the change point. This paper provides a maximum likelihood estimator to identify the real time of a step change in phase II monitoring of binary profiles, in which the quality of a process is characterized by a logistic regression between the response and predictor variables. Simulation studies are provided to evaluate the effectiveness of the change point estimator.  相似文献   
77.
Railway Engineering Science - Congestion pricing is seen as an effective policy to address traffic congestion. In such policies where money, people and authorities are involved, the success...  相似文献   
78.
Steam-assisted gravity drainage (SAGD) is a thermal enhanced oil recovery technique through drilling of two horizontal wells. Effects of steam injection temperature, well rates, and their distance on oil recovery were analyzed and optimized. Steam temperature and well distances remarkably affect SAGD performance. Four metaheuristic algorithms (particle swarm optimization (PSO), imperialist competitive algorithm, cultural algorithm, and Bees algorithm) and pattern search optimization algorithm (PSA) are used for optimization. PSO performs better than other metaheuristics and PSA is the fastest one, while it is probable to be trapped in local optimums. Hybrid PSO-PS is proposed that starts with PSO and proceeds with PSA, and tested in an SAGD project and showed excellence over other techniques.  相似文献   
79.
Journal of Failure Analysis and Prevention - The wear and failure analysis of shell liners of a grinding mill is investigated. Metallurgical and tribological studies were conducted on the worn...  相似文献   
80.
The photoluminescence emission of nanoporous anodic aluminum oxide films formed in phosphoric acid is studied in order to explore their defect-based subband electronic structure. Different excitation wavelengths are used to identify most of the details of the subband states. The films are produced under different anodizing conditions to optimize their emission in the visible range. Scanning electron microscopy investigations confirm pore formation in the produced layers. Gaussian analysis of the emission data indicates that subband states change with anodizing parameters, and various point defects can be formed both in the bulk and on the surface of these nanoporous layers during anodizing.  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