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   3740篇
  免费   166篇
  国内免费   7篇
电工技术   57篇
综合类   9篇
化学工业   515篇
金属工艺   67篇
机械仪表   75篇
建筑科学   288篇
矿业工程   14篇
能源动力   133篇
轻工业   358篇
水利工程   45篇
石油天然气   15篇
无线电   296篇
一般工业技术   658篇
冶金工业   400篇
原子能技术   20篇
自动化技术   963篇
  2024年   6篇
  2023年   21篇
  2022年   32篇
  2021年   68篇
  2020年   52篇
  2019年   70篇
  2018年   102篇
  2017年   119篇
  2016年   107篇
  2015年   98篇
  2014年   114篇
  2013年   283篇
  2012年   229篇
  2011年   285篇
  2010年   220篇
  2009年   196篇
  2008年   260篇
  2007年   222篇
  2006年   210篇
  2005年   159篇
  2004年   116篇
  2003年   117篇
  2002年   124篇
  2001年   75篇
  2000年   76篇
  1999年   65篇
  1998年   51篇
  1997年   53篇
  1996年   47篇
  1995年   46篇
  1994年   31篇
  1993年   21篇
  1992年   30篇
  1991年   18篇
  1990年   17篇
  1989年   18篇
  1988年   14篇
  1987年   17篇
  1986年   12篇
  1985年   16篇
  1984年   20篇
  1983年   7篇
  1982年   10篇
  1981年   8篇
  1980年   6篇
  1979年   14篇
  1978年   8篇
  1976年   6篇
  1975年   4篇
  1969年   3篇
排序方式: 共有3913条查询结果,搜索用时 15 毫秒
151.
The determination of pesticide residues in animal samples requires several analytical steps which may be time-consuming extraction procedures and with a small scope. For fat-soluble pesticides, the determination of fat is essential as they tend to bioaccumulate in fat. As to address these concerns, an easy acetonitrile-based multiresidue method combined with GC-MS-MS technology for the determination of the fat-soluble analytes was developed and validated on animal products. Analytes from several chemical classes such as diphenyl ethers, pyrethroids, organochlorides, triazoles, carbamide, chlorophenyls, dinitroaniline, organophosphorus, chloroacetamides, benzamides, aromatic hydrocarbon and dicarboximide known, due to their fat-soluble property, to bioaccumulate in animal tissues were selected. The method showed acceptable linearity (r?≥?0.99) and accuracy with recoveries between 70 and 120 % and precision with SDR?≤?20 % for the majority of the analytes studied. For the analytes that presented accuracy and precision values outside the acceptable limits, the method still is able to serve as a semi-quantitative method. The contribution of the determination of the fat in the results was also investigated. The limit of detection was set at 0.003 mg/kg. The proposed methodology was applied to meat and offal samples from the regional market in Attiki (Greece).  相似文献   
152.
This paper narrates the project management of the construction of the Florence Duomo by Filippo Brunelleschi in the fifteenth century. This was the most significant dome project in Europe in 1300 years, and possibly the most significant, innovative and complex project of the Renaissance era (Colombo and Lanzavecchia, 1997). It still stands as the largest brick dome ever built. In order to achieve what seemed technically impossible at the time, Brunelleschi researched and adapted the construction and project management of the Pantheon in Rome in the second century. The paper allows us in turn to learn both product and process innovation from this case study, both of which are essential to contemporary project management practice. The case is valuable in understanding key drivers of project management success, and illustrates the substantial potential for learning, and therefore knowledge transfer, from previous historical projects and experiences.  相似文献   
153.
154.
Abstract

Savings have long been an essential source of funding for credit. Whether in Europe, North America, Africa, Asia or Latin America, community-based financial institutions have relied on deposits to make financial services accessible to moderate-income borrowers. Despite the foundational role savings and loans have had in financial sector development, emerging markets have largely overlooked the important role these institutions can have in providing shelter credit in their own contexts. Savings and Credit Cooperative Organisations (SACCOs) in the Republic of Kenya illustrate the potential model for deposit-based lending to deliver housing finance for many of the country’s underserved prospective borrowers. This study draws upon the experiences of several savings and loan associations in the industrialized world with applications towards improving the Kenyan SACCO model that provides the most extensive credit union loans on the African continent. The article concludes community finance institutions merit strong consideration towards helping overcome the housing finance sector underdevelopment too often experienced in the developing world.  相似文献   
155.
156.
157.
158.
159.
160.
流行快报     
影响2012春夏零售市场的关键风格致命对比The attraction of opposites冷静与混乱:安静与嘈杂:朴素与修饰;历史与将来。这真的是充满对立面的季节,既有最新的高科技面料,有趣的表面效果和新颖的比例层次,也有冲击力极强的图案,对比强烈的触感和极端紧身的造型。如果你具备优秀的整合能力,在两极之间找到平衡点,使新样式保持可靠性的同时又具有原创性。  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