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   568篇
  免费   30篇
  国内免费   2篇
电工技术   6篇
综合类   4篇
化学工业   118篇
金属工艺   7篇
机械仪表   11篇
建筑科学   29篇
能源动力   11篇
轻工业   96篇
水利工程   2篇
无线电   33篇
一般工业技术   100篇
冶金工业   135篇
原子能技术   8篇
自动化技术   40篇
  2023年   8篇
  2022年   2篇
  2021年   26篇
  2020年   13篇
  2019年   12篇
  2018年   5篇
  2017年   20篇
  2016年   14篇
  2015年   16篇
  2014年   9篇
  2013年   26篇
  2012年   17篇
  2011年   21篇
  2010年   13篇
  2009年   13篇
  2008年   19篇
  2007年   18篇
  2006年   24篇
  2005年   15篇
  2004年   19篇
  2003年   16篇
  2002年   15篇
  2001年   14篇
  2000年   10篇
  1999年   12篇
  1998年   32篇
  1997年   21篇
  1996年   16篇
  1995年   10篇
  1994年   15篇
  1993年   12篇
  1992年   8篇
  1991年   3篇
  1990年   7篇
  1989年   14篇
  1988年   10篇
  1987年   13篇
  1986年   6篇
  1985年   7篇
  1984年   5篇
  1983年   7篇
  1982年   2篇
  1981年   3篇
  1978年   3篇
  1977年   3篇
  1976年   9篇
  1975年   4篇
  1974年   2篇
  1970年   4篇
  1956年   1篇
排序方式: 共有600条查询结果,搜索用时 15 毫秒
1.
2.
The objective of this paper is to identify and analyse factors that are important for winning acceptance of wind-energy parks on the local level. The developers of wind-energy parks need to know how to manage “social acceptance” at the different stages of planning, realisation and operation. Five case studies in France and Germany focused on factors of success in developing a wind-energy project on a given site and illuminated how policy frameworks influence local acceptance. Our hypothesis is that these factors fall into two categories: institutional conditions, such as economic incentives and regulations; and site-specific conditions (territorial factors), such as the local economy, the local geography, local actors, and the actual on-site planning process (project management).  相似文献   
3.
The authors present three different examples demonstrating the possibility of synchronising hyperchaotic oscillators via a single variable  相似文献   
4.
Photosystem II membranes, dialyzed against a Cl(-)-free buffer to remove bound Cl-, lost about 65% of the control activity. A light-intensity study of the Cl(-)-free membranes showed that all PS II centers were able to evolve oxygen at about 35% of the control rate when measured in Cl(-)-free medium. The Cl(-)-depleted membranes were immediately (< 15 s) reactivated to 85-90% of the original activity by the addition of fairly high concentrations of Cl- (Kd = 0.5 mM), but both Cl- and the activity were promptly lost when the membranes immediately after reactivation were diluted in a Cl(-)-free medium. However, stabilization of Cl(-)-binding could be accomplished by prolonged incubation in the presence of Cl-. The transition to stable binding, followed using 36Cl-, occurred over several minutes. The stable binding was further characterized by a Kd of 20 microM and a t1/2 for dissociation of about 1h [Lindberg et al. (1993) Photosynth. Res. 38, 401-408]. The effects on S2 signals of removal of Cl- were studied using EPR. The depletion of Cl- was accompanied by a shift in intensity toward the g = 4.1 signal at the expense of the multiline signal. When Cl- or Br- but not F- was added to the depleted PS II membranes, the original distribution of the signals was immediately (< 30 s) restored. We propose that Cl(-)-binding responsible for high oxygen-evolution activity and normal EPR properties of the S2 state may occur either as high affinity (Kd = 20 microM) and slowly exchanging (t1/2 = 1 h), or as low affinity (Kd = 0.5 mM) and rapidly exchanging (t1/2 < 15 s). Our results suggest that Br- but not F- has a mode of binding similar to that of Cl-. The high-affinity state is the normal state of binding, but once Cl- has been removed, it will first rebind as low-affinity, rapidly exchanging followed by conversion into a high-affinity, slowly exchanging mode of binding.  相似文献   
5.
6.
7.
8.
9.
A zero-degree spectrometer for tagging η mesons on the CELSIUS/WASA facility is described, and its characteristics are presented. Tagging of η mesons is performed by detecting 3He ions produced by reaction pd3Heη close to the production threshold. The low background level (<2%) is in good agreement with the data obtained earlier on the SATURNE accelerator.  相似文献   
10.
The purpose of this study was to examine the relationship of job satisfaction to job difficulty and worthiness, reported by the clinical psychologists who worked at medical institutions. A mail survey of 748 clinical psychologists working at hospital and clinics revealed the following results. First, job satisfaction was related more to job situation than job content. Also, job satisfaction was low among those who worked at non-university psychiatric or geriatric hospitals, who did not practice psychotherapy, and who were not in education, research, or management. In addition, compared to the high job satisfaction group, the low group perceived more incongruity between institutional climate and their psychological work, felt being less valued by other professionals, were less able to function fully as a practicing psychologist, and experienced more role ambiguity as a clinical psychologist in a hospital setting.  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