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   2820篇
  免费   8篇
电工技术   12篇
综合类   4篇
化学工业   71篇
金属工艺   7篇
机械仪表   5篇
建筑科学   23篇
矿业工程   3篇
能源动力   14篇
轻工业   52篇
水利工程   12篇
石油天然气   1篇
无线电   38篇
一般工业技术   56篇
冶金工业   2466篇
原子能技术   5篇
自动化技术   59篇
  2023年   2篇
  2021年   9篇
  2020年   4篇
  2019年   6篇
  2018年   3篇
  2017年   10篇
  2016年   7篇
  2015年   2篇
  2014年   11篇
  2013年   24篇
  2012年   9篇
  2011年   15篇
  2010年   14篇
  2009年   8篇
  2008年   13篇
  2007年   14篇
  2006年   17篇
  2005年   25篇
  2004年   18篇
  2003年   10篇
  2002年   11篇
  2001年   15篇
  2000年   9篇
  1999年   83篇
  1998年   791篇
  1997年   431篇
  1996年   308篇
  1995年   173篇
  1994年   134篇
  1993年   157篇
  1992年   23篇
  1991年   27篇
  1990年   29篇
  1989年   39篇
  1988年   36篇
  1987年   28篇
  1986年   33篇
  1985年   31篇
  1984年   6篇
  1983年   14篇
  1982年   4篇
  1981年   13篇
  1980年   19篇
  1979年   13篇
  1978年   9篇
  1977年   45篇
  1976年   103篇
  1975年   7篇
  1973年   3篇
  1971年   5篇
排序方式: 共有2828条查询结果,搜索用时 15 毫秒
1.
Few jurisdictions have translated internationally agreed social impact assessment (SIA) principles into statutory provisions. Governments and regulatory bodies tend to provide developers with high-level frameworks, or require that social impacts be ‘considered’, without specifying how this is to be done. In Australia, this lack of clarity leaves all parties uncertain about requirements for SIA. The New South Wales (NSW) Government’s 2017 release of the SIA guideline for State-significant mining, petroleum and extractive industry development represents an attempt to clarify requirements and provide guidance. In this paper, we describe the process of bringing this guideline to fruition from the perspective of being directly involved in its development, and highlight the challenges involved in integrating leading-practice principles into the state’s pre-existing policy framework. While the guideline represents a significant advance in policy-based SIA guidance, some aspects leave room for improvement. The real test of the guideline’s impact will lie in its influence on SIA practice in NSW, and ultimately in social outcomes for communities affected by resources projects.  相似文献   
2.
3.
The percentage of long-term survivors after intensive chemotherapy and the outcome of MDS patients who achieve partial remission (PR) with intensive chemotherapy (IC) are not known. Between 1981 and 1996 we treated 99 patients with de novo MDS who had high-risk MDS or progression to AML, with IC. 41 (41%) achieved CR, 16 (16%) achieved partial remission (PR), 26 (26%) had failure, and 16 (16%) died in aplasia. Eight of the patients who achieved CR were autografted, three were allografted and the remaining cases received moderate consolidation chemotherapy. After IC, the 16 PR patients fulfilled the criteria for RA in 15 cases and CMML in one case. Median PR duration was 17 months, and three PR were > 3 years (39, 50+, 82+ months). Median actuarial survival of patients who achieved PR and CR was 18 months and 20 months from the onset of IC, respectively (difference not significant). Of the 71 patients treated before 1993, with sufficient follow-up, 10 (14%) had survived > 4 years (long-term survivors). Four of them were alive in first CR after 49+ to 110+ months and probably cured, two were alive in PR after 50+ and 82+ months and four had died after 49-78 months. Long-term survivors were characterized by a significantly higher incidence of RAEB-T at diagnosis, and with normal or favourable cytogenetic findings. In patients with RAEB-T at diagnosis included before 1993, 8/23 (35%) cases who had no unfavourable karyotype had survived > 4 years. Our findings suggest that MDS patients who achieve PR with IC, and not only those who achieve CR, can benefit from this type of treatment. The percentage of long-term survivors remains low, however, and is almost restricted to patients with RAEB-T at diagnosis and no unfavourable karyotype.  相似文献   
4.
5.
6.
The aditi deductive database system   总被引:2,自引:0,他引:2  
Deductive databases generalize relational databases by providing support for recursive views and non-atomic data. Aditi is a deductive system based on the client-server model; it is inherently multi-user and capable of exploiting parallelism on shared-memory multiprocessors. The back-end uses relational technology for efficiency in the management of disk-based data and uses optimization algorithms especially developed for the bottom-up evaluation of logical queries involving recursion. The front-end interacts with the user in a logical language that has more expressive power than relational query languages. We present the structure of Aditi, discuss its components in some detail, and present performance figures.  相似文献   
7.
We have compared the duration of motor block produced by four local anaesthetics administered into a chronically implanted subarachnoid catheter in rabbits. Each group (n = 6) received four different doses of amethocaine, bupivacaine, lignocaine or procaine, and the duration of the resulting motor block was assessed. Dose-response curves were plotted for each drug. As a measure of activity of the anaesthetics, we used the dose of each drug required to produce block of 60-min duration (D60 min) and the correlation between D60 min and different drug properties was examined. An inverse linear correlation (r = 0.995; P < 0.01) was observed between log D60 min and the log of the partition coefficient of the local anaesthetics. No correlation was found between the effect and degree of protein binding, pKa or molecular weight. These results suggest that, in spinal anaesthesia, the partition coefficient could be used as a predictor of the duration of anaesthetic action.  相似文献   
8.
Bound-state beta decay of highly ionized atoms   总被引:1,自引:0,他引:1  
  相似文献   
9.
Agenesis of the corpus callosum in a mother and son   总被引:1,自引:0,他引:1  
Most reported familial cases of agenesis of the corpus callosum have followed either an autosomal recessive or an X-linked recessive pattern of inheritance. To the best of our knowledge, there is only one previous report of a family showing clear-cut autosomal dominant inheritance. We present the second such family, among whom a mother and her son had moderately severe coordination problems and low-normal intelligence. We suggest that agenesis of the corpus callosum, when transmitted as an autosomal dominant trait, is clinically characterized by a relatively milder phenotype than that occurring when inheritance is either autosomal or X-linked recessive and may be more common than has been thought.  相似文献   
10.
In vivo dosimetry performed with semiconductor detectors is a reliable method for patient dose control. The purpose of this study is to evaluate the perturbations introduced in the patient's absorbed dose distribution by three types of commercially available diodes (Isorad, Sun Nuclear Corp.; model 114200, 114300 and 114400) from the same company and to present possible solutions for minimizing this side-effect.  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