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   93篇
  免费   4篇
化学工业   7篇
金属工艺   3篇
机械仪表   4篇
建筑科学   4篇
轻工业   3篇
水利工程   1篇
无线电   9篇
一般工业技术   21篇
冶金工业   22篇
自动化技术   23篇
  2021年   1篇
  2020年   2篇
  2019年   1篇
  2018年   1篇
  2016年   1篇
  2015年   3篇
  2014年   2篇
  2013年   6篇
  2012年   4篇
  2011年   2篇
  2010年   3篇
  2009年   1篇
  2008年   3篇
  2007年   6篇
  2006年   5篇
  2005年   2篇
  2004年   4篇
  2003年   3篇
  2002年   2篇
  2001年   5篇
  2000年   1篇
  1999年   3篇
  1998年   4篇
  1997年   3篇
  1996年   1篇
  1994年   3篇
  1993年   2篇
  1992年   2篇
  1991年   2篇
  1990年   3篇
  1984年   1篇
  1982年   1篇
  1981年   2篇
  1980年   3篇
  1978年   2篇
  1977年   2篇
  1976年   1篇
  1974年   1篇
  1973年   1篇
  1971年   2篇
排序方式: 共有97条查询结果,搜索用时 15 毫秒
1.
In May 2006, the US Army Research Laboratory and UK Ministry of Defense created the international technology alliance. The consortium of 26 partners including the ARL and MoD offers an open research environment in which leading US and UK companies and universities can collaborate (see table 1). It will also fuse the best aspects of the US Army's Collaborative Technology Alliances and UK MoD's Defense Technology Centers on an international scale. The ITA aims to develop flexible, distributed, and secure decision-making procedures to improve networked coalition operations. Network science is a young discipline we have limited information models and network theories to describe the behavior and scaling of large, complex mobile ad hoc networks.1 moreover, you can't understand a coalition network's performance without understanding its cognitive and sociocultural aspects and physical characteristics. A key ITA goal is to perform basic research in network-centric coalition decision making across four technical areas: network theory, security across a system of systems, sensor information processing and delivery, and distributed coalition planning and decision making, 2. we focus on the last area because this is where intelligent systems will play the biggest role.  相似文献   
2.
Doses from intravenous intakes of 59Fe or 57Co chloride during pregnancy were estimated. Near term fetal organ doses were derived via the MIRDOSE3 newborn phantom, with mean dose/cumulated activity (S) values rescaled for compatibility with near term fetus whole body S. A detailed in vivo biodistribution database provided indications of residence times in important maternal and fetal organs. 59Fe doses to the fetus whole body from early to late pregnancy were 7-11 mGy MBq(-1) (8.5-14.3 mSv MBq(-1)), similar to that to the mother. Doses to near term fetal spleen (59 mGy MBq(-1)), liver (36), and red marrow (9) were similar or higher than to the mother. 57Co doses to fetus whole body from early to late pregnancy were 0.7-3.3 mGy MBq(-1) (2.5-8.2 mSv MBq(-1)), similar or higher than to the mother. Doses to near term fetal small intestine (34 mGy MBq(-1)). liver (4.7) and red marrow (2.7) were similar or higher than to the mother.  相似文献   
3.
Molecular resists, such as triphenylene derivatives, are small carbon rich molecules, and thus give the potential for higher lithographic resolution and etch durability, and lower line width roughness than traditional polymeric compounds. Their main limitation to date has been poor sensitivity. A new triphenylene derivative molecular resist, with pendant epoxy groups to aid chemically amplified crosslinking, was synthesized and characterized. The sensitivity of the negative tone, pure triphenylene derivative when exposed to an electron beam with energy 20 keV was ~ 6 × 10–4 C cm–2, which increased substantially to ~ 1.5 × 10–5 C cm–2 after chemical amplification (CA) using a cationic photoinitiator. This was further improved, by the addition of a second triphenylene derivative, to ~ 7 × 10–6 C cm–2. The chemically amplified resist demonstrated a high etch durability comparable with the novolac resist SAL 601. Patterns with a minimum feature size of ~ 40 nm were realized in the resist with a 30 keV electron beam.  相似文献   
4.
5.
6.
A clock-reaction is a chemical reaction which gives rise to an initial induction period before a significant change in concentration of one of the chemical species occurs. In this paper the development of travelling waves from a particular class of inhibited autocatalytic clock-reactions is analysed. The numerical solutions show that, after the induction period, a propagating reaction-diffusion front is initiated. This front is seen to accelerate initially and then to become a constant-speed travelling wave. An asymptotic analysis of the large-time travelling-wave behaviour is given and from this it is possible to fix a minimum wave speed. The asymptotic predictions of the wave speed are found to agree well with those of the numerical solution.  相似文献   
7.
8.
An important emerging issue in chemical carcinogenesis is the role that products of endogenous metabolism play in formation of covalently modified DNA. One example is the formation of alpha, beta-unsaturated aldehydes as a result of endogenous and drug-stimulated lipid peroxidation. Malondialdehyde (MDA), crotonaldehyde (CR), 2-hexenal (HX), and 4-hydroxy-2-nonenal (HNE) react covalently with 2'-deoxyguanosine (dG) and 2'-deoxyadenosine (dA) residues on DNA to form promutagenic cyclic adducts that may be important in the etiology of cancer in humans and animals. The accurate quantification of such adducts provides a powerful tool in molecular epidemiology for assessing carcinogenic risks from various lifestyle choices (e.g. diet, drug use) in humans. 32P-Postlabeling is recognized as one of the most sensitive methods available for detection of DNA adducts in human tissues, but without adequate validation such methodology can yield inaccurate quantitative measurements. We have used LC separations in conjunction with electrospray ionization MS and tandem MS (triple quadrupole and hybrid quadrupole-orthogonal acceleration time of flight analyzers) to characterize MDA-, CR-, HX- and HNE-modified dG and nucleotide (3'- and 5'-monophosphate; 3',5'-bisphosphate) adducts. These data have been used to validate 32P-postlabeling methods for quantification of low level MDA-dG adducts formed in DNA of human and animal tissues. Availability of reliable methods for quantification of endogenous DNA damage in humans and animals is essential for determining unknown etiologies of cancer and for the assessment of cancer risks in humans.  相似文献   
9.
10.
Previous research has indicated that individual foods or beverages are ingested independently and do not produce adjustments to the intake of other constituents in the diet (de Castro, 1993; Wilson, 1991). In order to eliminate time of day as a potential contaminant, the present study investigated the accommodation of foods and beverages into the amount ingested at large evening meals only. Adults (n = 601) were paid to maintain detailed diaries of the timings, quantities and preparation techniques of everything they ingested for seven consecutive days. With the exceptions of soup, beef and chicken, 12 out of 15 types of drinks or foods were found to add to the total calories ingested in evening meals without displacing calories ingested in other forms, while ingestion of non-caloric diet sodas was not associated with differences in intake. The fat and protein, but not carbohydrate, contents of the items correlated with a measure of the satiating properties of the particular food or beverage, namely the correlation between the amount ingested of the particular type and the amounts of other nutrients ingested in the meal. The results confirm that intake at a meal is quite elastic and can be significantly influenced by the presence or absence of particular components of the meal and their constituents.  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