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   1766篇
  免费   14篇
  国内免费   1篇
电工技术   21篇
化学工业   170篇
金属工艺   52篇
机械仪表   29篇
建筑科学   35篇
矿业工程   9篇
能源动力   13篇
轻工业   73篇
水利工程   9篇
石油天然气   67篇
无线电   110篇
一般工业技术   413篇
冶金工业   552篇
原子能技术   38篇
自动化技术   190篇
  2021年   19篇
  2020年   20篇
  2019年   29篇
  2018年   33篇
  2017年   24篇
  2016年   32篇
  2015年   17篇
  2014年   28篇
  2013年   59篇
  2012年   44篇
  2011年   51篇
  2010年   49篇
  2009年   37篇
  2008年   44篇
  2007年   44篇
  2006年   62篇
  2005年   39篇
  2004年   31篇
  2003年   32篇
  2002年   27篇
  2001年   22篇
  2000年   16篇
  1999年   39篇
  1998年   120篇
  1997年   81篇
  1996年   49篇
  1995年   39篇
  1994年   38篇
  1993年   44篇
  1992年   25篇
  1991年   20篇
  1990年   21篇
  1989年   21篇
  1988年   17篇
  1987年   34篇
  1986年   25篇
  1985年   24篇
  1984年   19篇
  1983年   21篇
  1982年   22篇
  1980年   18篇
  1978年   20篇
  1977年   39篇
  1976年   48篇
  1974年   16篇
  1973年   16篇
  1970年   19篇
  1969年   20篇
  1968年   19篇
  1966年   16篇
排序方式: 共有1781条查询结果,搜索用时 78 毫秒
81.
Conclusions The method developed was used to analyze the separation of stable chromium isotopes (in the form CrO2F2) as well as some other elements in the type of centrifuge studied. It was determined that the efficiency as a function of the parameter studied in the present work is similar. Moreover, the results made it possible to determine the dependence of the separation capability on the molecular mass and physical properties of the working gases. Moscow Engineering Physics Institute. Translated from Atomnaya énergiya, Vol. 76, No. 6, pp. 491–495, June, 1994.  相似文献   
82.
OBJECTIVE: The aim of this study was to determine if omeprazole improves pulmonary function and quality of life in asthmatics with gastroesophageal reflux. METHODS: This was a double blind, randomized, placebo-controlled cross-over trial. After a 4-wk lead-in period, nine patients with documented asthma and gastroesophageal reflux, were prescribed either omeprazole 20 mg, daily or placebo for 8 wk and then crossed over to the alternate treatment. Outcome measurements included: forced expiratory volume at 1 s (FEV1), peak expiratory flow rate (PEFR), and responses on the Asthma Quality of Life Questionnaire, a validated disease specific measure of functional status. RESULTS: After omeprazole treatment, compared with placebo, patients had higher mean morning and evening PEFR, mean absolute difference (95% CI): morning: 37.8 L/min. (10.9-64.6), evening: 31.2 (3.2-59.2). Omeprazole treatment led to higher mean overall scores on the Asthma Quality of Life Questionnaire, and on the subdomains of activity limitation, symptoms, and emotions (p = 0.039, 0.049, 0.024, 0.040). A trend toward higher FEV1 (mean: 15.6% difference) with omeprazole failed to reach statistical significance (p > 0.2). CONCLUSIONS: After taking omeprazole for 8 wk, asthmatics with GER have better PEFR and quality of life than after placebo.  相似文献   
83.
Inaccurate self-awareness is a common finding after traumatic brain injury. Such impaired awareness has been hypothesized to limit patients' eventual functional outcomes by decreasing motivation for treatment and resulting in selection of inappropriate long-term goals. Previous investigations of the association between impaired awareness and employment outcome have produced inconsistent results. The present article reviews these studies and presents the results of our new investigation of this issue. In addition, we studied the comparability of two methods of measuring impaired awareness. Results provided strong support for a positive relationship between accurate self-awareness and favorable employment outcome at follow-up.  相似文献   
84.
85.
86.
87.
88.
Summary Proof rules are presented for an extension of Hoare's Communicating Sequential Processes. The rules deal with total correctness; all programs terminate in the absence of deadlock. The commands send and receive are treated symmetrically, simplifying the rules and allowing send to appear in guards. Also given are sufficient conditions for showing that a program is deadlock-free. An extended example illustrates the use of the technique.This research was supported in part by the National Science Foundation under grant MCS-7622360.  相似文献   
89.
90.
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