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   862篇
  免费   6篇
电工技术   15篇
综合类   1篇
化学工业   52篇
金属工艺   26篇
机械仪表   16篇
建筑科学   20篇
矿业工程   2篇
能源动力   5篇
轻工业   27篇
水利工程   4篇
石油天然气   6篇
无线电   80篇
一般工业技术   84篇
冶金工业   364篇
原子能技术   12篇
自动化技术   154篇
  2021年   7篇
  2018年   13篇
  2016年   3篇
  2015年   5篇
  2014年   7篇
  2013年   32篇
  2012年   10篇
  2011年   15篇
  2010年   25篇
  2009年   26篇
  2008年   18篇
  2007年   25篇
  2006年   10篇
  2005年   15篇
  2004年   23篇
  2003年   9篇
  2002年   9篇
  2001年   10篇
  2000年   12篇
  1999年   21篇
  1998年   82篇
  1997年   47篇
  1996年   47篇
  1995年   23篇
  1994年   28篇
  1993年   33篇
  1992年   13篇
  1991年   5篇
  1990年   14篇
  1989年   17篇
  1988年   15篇
  1987年   14篇
  1986年   10篇
  1985年   10篇
  1984年   24篇
  1983年   12篇
  1982年   19篇
  1981年   18篇
  1980年   10篇
  1979年   7篇
  1978年   9篇
  1977年   15篇
  1976年   17篇
  1975年   10篇
  1974年   15篇
  1973年   10篇
  1972年   11篇
  1971年   6篇
  1970年   6篇
  1966年   5篇
排序方式: 共有868条查询结果,搜索用时 31 毫秒
1.
2.
We could not imagine a more appropriate inauguration of the Psychology of Aesthetics, Creativity, and the Arts (PACA) going to four issues per year than with a special issue honoring the life and work of the great aesthetician and psychologist, Rudolf Arnheim. PACA is off to a great start. With this move to four issues per year, we are restarting our numbering system, so this special issue is Volume 1, Issue 1. As you read the articles in this issue, we hope that you enjoy reflecting on how much Rudolf Arnheim has contributed to the field of psychology of aesthetics. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
3.
4.
5.
Caspases are fundamental components of the mammalian apoptotic machinery, but the precise contribution of individual caspases is controversial. CPP32 (caspase 3) is a prototypical caspase that becomes activated during apoptosis. In this study, we took a comprehensive approach to examining the role of CPP32 in apoptosis using mice, embryonic stem (ES) cells, and mouse embryonic fibroblasts (MEFs) deficient for CPP32. CPP32(ex3-/-) mice have reduced viability and, consistent with an earlier report, display defective neuronal apoptosis and neurological defects. Inactivation of CPP32 dramatically reduces apoptosis in diverse settings, including activation-induced cell death (AICD) of peripheral T cells, as well as chemotherapy-induced apoptosis of oncogenically transformed CPP32(-/-) MEFs. As well, the requirement for CPP32 can be remarkably stimulus-dependent: In ES cells, CPP32 is necessary for efficient apoptosis following UV- but not gamma-irradiation. Conversely, the same stimulus can show a tissue-specific dependence on CPP32: Hence, TNFalpha treatment induces normal levels of apoptosis in CPP32 deficient thymocytes, but defective apoptosis in oncogenically transformed MEFs. Finally, in some settings, CPP32 is required for certain apoptotic events but not others: Select CPP32(ex3-/-) cell types undergoing cell death are incapable of chromatin condensation and DNA degradation, but display other hallmarks of apoptosis. Together, these results indicate that CPP32 is an essential component in apoptotic events that is remarkably system- and stimulus-dependent. Consequently, drugs that inhibit CPP32 may preferentially disrupt specific forms of cell death.  相似文献   
6.
The study revealed that Fixed Price, Cost Plus and Purchased Labour contracts are the top three maintenance contracts adopted whilst Unit Price, Cost Plus A Percentage Fee contracts are alternatives used in the Kingdom. Some other types of maintenance contract were thought to be inappropriate by ministry departments.  相似文献   
7.
Of 1,666 patients who underwent fine needle aspiration for breast lumps, 4 developed pneumothorax as a complication. The incidence of this complication in our patients is 1:417. The clinical manifestations were immediate chest pain, shoulder pain and, occasionally, dyspnea that developed later. Observation is sufficient treatment in most patients, and rarely is drainage of the pneumothorax required.  相似文献   
8.
Translated from Izmeritel'naya Tekhnika, No. 4, pp. 38–39, April, 1989.  相似文献   
9.
10.
The solidification sequences in aluminum containing 8 and 16 wt pct iron are described in terms of the formation of metastable and stable primary intermetallic phases. These alloys were studied in the chill-cast and splat-quenched conditions, and marked differences in microstructure due to the different cooling rates were observed. Contrary to previous work, it is proposed that the 50-nm intercellular particles observed in the “zone A” regions of the splat-quenched alloys are primary in nature; this may account, in part, for their remarkable thermal stability.  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