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   1542篇
  免费   31篇
  国内免费   12篇
电工技术   25篇
综合类   1篇
化学工业   288篇
金属工艺   29篇
机械仪表   66篇
建筑科学   113篇
矿业工程   3篇
能源动力   28篇
轻工业   157篇
水利工程   18篇
石油天然气   12篇
武器工业   1篇
无线电   97篇
一般工业技术   205篇
冶金工业   313篇
原子能技术   17篇
自动化技术   212篇
  2023年   10篇
  2021年   21篇
  2019年   21篇
  2018年   25篇
  2017年   22篇
  2016年   24篇
  2015年   15篇
  2014年   23篇
  2013年   112篇
  2012年   40篇
  2011年   54篇
  2010年   52篇
  2009年   47篇
  2008年   53篇
  2007年   56篇
  2006年   49篇
  2005年   45篇
  2004年   28篇
  2003年   44篇
  2002年   36篇
  2001年   27篇
  2000年   25篇
  1999年   32篇
  1998年   84篇
  1997年   45篇
  1996年   46篇
  1995年   29篇
  1994年   35篇
  1993年   26篇
  1992年   18篇
  1991年   17篇
  1990年   19篇
  1988年   18篇
  1987年   22篇
  1986年   15篇
  1985年   18篇
  1984年   27篇
  1983年   27篇
  1982年   22篇
  1981年   15篇
  1980年   15篇
  1979年   19篇
  1978年   18篇
  1977年   22篇
  1976年   27篇
  1975年   25篇
  1974年   10篇
  1973年   14篇
  1971年   11篇
  1970年   12篇
排序方式: 共有1585条查询结果,搜索用时 15 毫秒
1.
For users of an executive information system (EIS), the EIS interface is the system and is crucial to the EIS's success. These guidelines for designing EIS interfaces are based on studies of actual EIS interfaces that meet the unique information needs of executives.  相似文献   
2.
Hypersonic flight powered by airbreathing engines offers the potential for faster response time at long ranges, and reduced cost for access-to-space. In the present paper the operating environment of typical hypersonic vehicles are discussed, including results for the radiation equilibrium wall temperature of external vehicle surfaces and the flow properties through three sample engines spanning the range of hydrocarbon-fueled Mach 4-8 flight and hydrogen-fueled flight at speeds up to Mach 17. Flow conditions at several locations through the sample engines were calculated to provide indications of the required operating flow environment. Additional system consideration such a seals, joints, vehicle integration and in-service engineering are addressed.  相似文献   
3.
Thin films of Praseodymium doped AlN are deposited on silicon (111) substrates at 77 K and 950 K by rf magnetron sputtering method. About 500–1000 nm thick films are grown at 100–200 watts RF power and 5–8 mTorr nitrogen, using a metal target of Al with Pr. X-rays diffraction results show that films deposited at 77 K are amorphous and those deposited at 950 K are crystalline. Cathodoluminescence studies are performed at room temperature and luminescence peaks are observed in a wide range from ultraviolet to infrared region. The most intense peak is obtained in green at 526 nm from amorphous films as a result from 3P13H5 transition. In crystalline films the intense peak was obtain in red at 648 nm as a result from 3P03F2 transition. Films are thermally activated at 1300 K for half an hour in a nitrogen atmosphere. Thermal activation enhances the intensity of luminescence. Two peaks at 488 nm and 505 nm merged after thermal activation, giving rise to a single peak at 495 nm.  相似文献   
4.
Elder mistreatment, both abuse and neglect, is an important health care problem for women since they are involved as victims and as perpetrators. The incidence of both forms of such mistreatment is increasing, and both often occur within the context of long-term care. Elder abuse occurs in both unidirectional and dual directional forms, and includes parent abuse and spouse abuse. Elder neglect occurs in two forms; neglect by others and self-neglect. While elderly men and women are both neglected and/or abused, women may suffer greater physical and psychological consequences. To date, researchers have inadequately addressed the relevance of gender to both forms of elder mistreatment. This literature review addresses what is currently known about elder abuse and neglect that is of particular relevance to older women.  相似文献   
5.
In 1993, the American Society for Testing and Materials carried out a field test of newly calculated tristimulus weighting factors. These weighting factors had been calculated by a method proposed by Venable. the test also included a method of correction for bandpass dependence put forth by Stearns. the purpose of the trial was to assess the possible reduction in bandpass dependence introduced by each of these sets of weights. A large number of sets of spectral data were gathered from the cooperators in the field test. Results of integration by the various sets of tristimulus weighting factors were calculated. A total of 15 120 color differences were calculated and statistics were derived to test the probable error resulting from each method of correction. Errors attributable to bandpass dependence were on the order of a few tenths to as much as one CIELAB unit when uncorrected weight sets were used. These errors could be reduced to a few hundreths of a CIELAB unit, and in some cases to a few thousandths of a unit, by employing one correcting strategy or the other. an overall mix of strategies was ultimately chosen to minimize the bandpass dependence over the entire range of weight sets. Utilizing this mixed strategy, the median error introduced into 10-nm integration by bandpass dependence was only 0.004 CIELAB units. © 1995 John Wiley & Sons, Inc.  相似文献   
6.
Although many devastated European cities have been studied, the bombing and reconstruction of key industrial sites and certain suburban residential zones in greater Paris have received little scholarly attention. Using archival sources, this article explores both destruction and reconstruction, and traces how homeless families shared apartments or endured years of 'temporary' accommodation in huts and other shelters. Post-war economic planning in France privileged the restoration of industrial and commercial sites; rebuilding of housing by the state, by housing co-operatives and by individual property owners received less support and progressed far more slowly. Today, the visual legacy of reconstruction is easily confused with that of completely new post-war apartments; however its origin, if not its architecture, is distinctively different and merits recognition in its own right.  相似文献   
7.
8.
Two major areas of concern for IS managers are the use of outsourcing and the often-expressed view that little competitive advantage has been gained from information processing. These developments have begun to mirror events in other professions from a bygone age. By looking outside the IS field for some perspective, we may avert a similar outcome and better define the role of IS in the organization.  相似文献   
9.
10.
The prevalence of several paraneoplastic syndromes associated with ovarian cancer was determined from a clinicopathological study of 908 patients with primary ovarian malignancy in the North East Thames Region. The diversity and rarity of these manifestations are great and the explanation for them is difficult. Circumstantial evidence suggests that in some cases an autoimmune phenomenon is the most plausible cause.  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