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   2157篇
  免费   156篇
  国内免费   1篇
电工技术   25篇
综合类   10篇
化学工业   737篇
金属工艺   36篇
机械仪表   28篇
建筑科学   69篇
矿业工程   7篇
能源动力   53篇
轻工业   241篇
水利工程   18篇
石油天然气   11篇
无线电   124篇
一般工业技术   388篇
冶金工业   318篇
原子能技术   3篇
自动化技术   246篇
  2023年   33篇
  2022年   130篇
  2021年   161篇
  2020年   74篇
  2019年   65篇
  2018年   87篇
  2017年   63篇
  2016年   89篇
  2015年   83篇
  2014年   82篇
  2013年   145篇
  2012年   127篇
  2011年   168篇
  2010年   100篇
  2009年   101篇
  2008年   101篇
  2007年   86篇
  2006年   78篇
  2005年   61篇
  2004年   63篇
  2003年   44篇
  2002年   43篇
  2001年   18篇
  2000年   24篇
  1999年   15篇
  1998年   38篇
  1997年   31篇
  1996年   21篇
  1995年   20篇
  1994年   18篇
  1993年   19篇
  1992年   12篇
  1991年   8篇
  1990年   8篇
  1989年   6篇
  1988年   8篇
  1987年   10篇
  1986年   4篇
  1985年   9篇
  1984年   4篇
  1983年   6篇
  1982年   3篇
  1981年   6篇
  1979年   7篇
  1977年   6篇
  1976年   10篇
  1975年   3篇
  1972年   2篇
  1970年   2篇
  1964年   2篇
排序方式: 共有2314条查询结果,搜索用时 46 毫秒
1.
2.
3.
4.
Prevalence rates of trauma and posttraumatic stress disorder (PTSD) were estimated from a probability sample of 2,509 adults from 4 cities in Mexico. PTSD was assessed according to Diagnostic and Statistical Manual of Mental Disorders (American Psychiatric Association, 1994) criteria using the Composite International Diagnostic Interview (CIDI; WHO, 1997). Lifetime prevalence of exposure and PTSD were 76% and 11.2%, respectively. Risk for PTSD was highest in Oaxaca (the poorest city), persons of lower socioeconomic status, and women. Conditional risk for PTSD was highest following sexual violence, but nonsexual violence and traumatic bereavement had greater overall impact because of their frequency. Of lifetime cases, 62% became chronic; only 42% received medical or professional care. The research demonstrates the importance of expanding the epidemiologic research base on trauma to include developing countries around the world. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
5.
Examined the theory that chronic migraine headaches can lead to permanent changes in brain function in 71 female college students. Ss were 20 classic migraineurs, 27 common migraineurs, and 24 controls. No significant group differences were found on the Halstead Reitan Neuropsychological Test Battery and additional memory tests. Classic migraineurs had significantly higher scores than common migraineurs on the Hysteria and Paranoia scales of the Minnesota Multiphasic Personality Inventory (MMPI) and significantly higher scores than the controls on Hypochondriasis and Hysteria scales. Explanations for the lack of cognitive deficits in this group are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
6.
Large, easily viewed status boards are commonly used in some healthcare settings such as emergency departments, operating theaters, intensive care units, and inpatient wards. Because these artefacts were developed by front-line users, and have little to no supervisory or regulatory control, they offer valuable insights into the theories of work and hazard held by those users. Although the status boards case were locally developed over many years for within-group coordination, they have also become useful for between-group coordination across organizational boundaries. In this paper, we compare and contrast the use of such status boards in two disparate settings: a US emergency department, and a UK pediatric ward, and note striking similarities in their form and usage, despite the large differences in setting.  相似文献   
7.
Healthcare institutions typically post their privacy practices online as privacy policy documents. We conducted a longitudinal study that examines the effects of HIPAA's enactment on a collection of privacy policy documents for a fixed set of organizations over a four-year period. We present our analysis of 24 healthcare privacy policy documents from nine healthcare Web sites, analyzed using goal mining, a content-analysis method that supports extraction of useful information about institutions' privacy practices from documents. We compare our results to our pre-HIPAA study of these same institutions' online privacy practices and evaluate their evolution in the presence of privacy laws  相似文献   
8.
This paper discusses the contested role of images in electronic editions, and summarizes some of the chief arguments for their inclusion. I then argue that, to truly determine the importance of images to the function of electronic editions, we must understand the contribution the image makes to the form of textual knowledge provided by the edition. I suggest a distinction between editions which are primarily pedagogical in their aims, those which aim above all at scholarly authority, and those which attempt to provide textual information as high-quality data which can be analysed and processed. I conclude that the latter represents the most significant future trend in electronic editing. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   
9.
Between February 1991 and April 1992, eight undergraduates at a US residential university and one at a nearby 2-year college contracted serogroup C meningococcal disease. A case-control investigation with 20 controls per case, oropharyngeal carriage surveys, and multilocus enzyme electrophoresis (MEE) of serogroup C isolates were used to identify factors contributing to the outbreak. All eight sterile-site isolates from cases were closely related by MEE and were similar (though not identical) to the strain associated with the 1991-1992 epidemic of meningococcal disease in eastern Canada. Disease was associated with cigarette smoking (p = 0.012), recent patronage of campus-area bars (p = 0.034), estimated amount of time spent in campus-area bars (p = 0.0003), and, especially, recent patronage of one specific bar, bar A (p = 0.0006; odds ratio = 23.1, 95% confidence interval 3.0-571.5). In carriage surveys, 1,528 throat cultures taken from (primarily student) noncases yielded only five (0.3%) strains that were identical by MEE to those from cases. Two of these were found among 22 cultures obtained from bar A employees in spring 1992. Some cases in this outbreak may have followed transmission of the epidemic strain in bar A. Campus bar environments may facilitate the spread of meningococcal disease among teenagers and young adults.  相似文献   
10.
We give a parametrized family of rational interval maps of degree two, each ergodic, exact and preserving a measure equivalent to a Lebesgue measure. The family includes the unique quadratic Chebyshev polynomial as its only polynomial map. We extend the family to other settings on the circle and real line. We also give numerical approximations to the entropy of the equivalent invariant measure and the Hausdorff dimension of the singular measure of maximal entropy.  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