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   500篇
  免费   5篇
  505篇
  2023年   6篇
  2020年   3篇
  2019年   7篇
  2018年   13篇
  2017年   15篇
  2016年   17篇
  2015年   12篇
  2014年   7篇
  2013年   40篇
  2012年   20篇
  2011年   21篇
  2010年   12篇
  2009年   9篇
  2008年   23篇
  2007年   15篇
  2006年   14篇
  2005年   18篇
  2004年   16篇
  2003年   21篇
  2002年   20篇
  2001年   11篇
  2000年   7篇
  1999年   7篇
  1998年   9篇
  1997年   5篇
  1996年   10篇
  1995年   8篇
  1993年   7篇
  1992年   4篇
  1990年   7篇
  1989年   4篇
  1988年   3篇
  1985年   3篇
  1984年   3篇
  1983年   9篇
  1982年   3篇
  1981年   12篇
  1980年   11篇
  1979年   3篇
  1978年   3篇
  1977年   7篇
  1976年   4篇
  1975年   5篇
  1974年   9篇
  1973年   8篇
  1972年   2篇
  1971年   2篇
  1970年   3篇
  1969年   8篇
  1968年   4篇
排序方式: 共有505条查询结果,搜索用时 15 毫秒
31.
Exposure to severe air pollution produces neuroinflammation and structural brain alterations in children. We tested whether patterns of brain growth, cognitive deficits and white matter hyperintensities (WMH) are associated with exposures to severe air pollution. Baseline and 1 year follow-up measurements of global and regional brain MRI volumes, cognitive abilities (Wechsler Intelligence Scale for Children-Revised, WISC-R), and serum inflammatory mediators were collected in 20 Mexico City (MC) children (10 with white matter hyperintensities, WMH+, and 10 without, WMH) and 10 matched controls (CTL) from a low polluted city. There were significant differences in white matter volumes between CTL and MC children - both WMH+ and WMH - in right parietal and bilateral temporal areas. Both WMH and WMH+ MC children showed progressive deficits, compared to CTL children, on the WISC-R Vocabulary and Digit Span subtests. The cognitive deficits in highly exposed children match the localization of the volumetric differences detected over the 1 year follow-up, since the deficits observed are consistent with impairment of parietal and temporal lobe functions. Regardless of the presence of prefrontal WMH, Mexico City children performed more poorly across a variety of cognitive tests, compared to CTL children, thus WMH+ is likely only partially identifying underlying white matter pathology. Together these findings reveal that exposure to air pollution may perturb the trajectory of cerebral development and result in cognitive deficits during childhood.  相似文献   
32.
A latent-variable study examined whether verbal and visuospatial working memory (WM) capacity measures reflect a primarily domain-general construct by testing 236 participants in 3 span tests each of verbal WM. visuospatial WM, verbal short-term memory (STM), and visuospatial STM. as well as in tests of verbal and spatial reasoning and general fluid intelligence (Gf). Confirmatory' factor analyses and structural equation models indicated that the WM tasks largely reflected a domain-general factor, whereas STM tasks, based on the same stimuli as the WM tasks, were much more domain specific. The WM construct was a strong predictor of Gf and a weaker predictor of domain-specific reasoning, and the reverse was true for the STM construct. The findings support a domain-general view of WM capacity, in which executive-attention processes drive the broad predictive utility of WM span measures, and domain-specific storage and rehearsal processes relate more strongly to domain-specific aspects of complex cognition.  相似文献   
33.
34.
Expert review sessions are often conducted to determine the content validity of scale items. The accurate quantification of content validity is usually limited by a relatively small number of experts as well as by a small number of rating categories. These factors, combined with the bounded and discrete nature of rating scale categories, hinder use of traditional methods for computing standard errors and confidence intervals. Using an application of the score method, researchers can construct an asymmetric interval that is better suited for these situations. SAS code is provided to automate the computations, and a discussion of two methods for using the obtained results for content validation decisionmaking follows.  相似文献   
35.
36.
37.
38.
Long-running multi-faceted intervention studies are particularly problematic in large complex organizations where traditional methods prove too resource intensive and can yield inaccurate and incomplete findings. This paper describes the first use of, longitudinal tracer methodology (LTM), a realist approach to evaluation, to examine the links between multiple complex intervention activities (processes) and their outcomes on a construction megaproject. LTM is especially useful when the researcher has little control over intervention delivery but has evidence drawn from multiple sources to evaluate the intervention activities effects over time. This methodology has rarely been deployed in complex organizational settings and not on a construction megaproject. This paper presents a case study of its use over a period of three years, on 24 construction sites forming London’s Thames Tideway Tunnel (Tideway) megaproject. The study examines the “transformational” power of occupational safety and health (OSH) interventions across the multiple organizations and supply chains in the megaproject. The study shows how the method can be adapted in-flight to accommodate shifting lines of inquiry as the intervention activities progress and change. This feature along with its resource-efficient operation, make it an attractive option where interventions are likely to have differential effects across multiple sites of enactment.  相似文献   
39.
The authors examined the construct of psychopathy as applied to 130 adolescent offenders using 3 psychopathy measures and a broad range of DSM-TV Axis I diagnoses and psychosocial problems. Measures used in the study included the following: (a) Psychopathy Checklist-Youth Version, (b) Antisocial Process Screening Device, (c) a modified version of the Self-Report Psychopathy-II scale, and (d) the Adolescent Psychopathology Scale. Results from this study offer incremental support for the construct validity of psychopathy in youth. Psychopathy evidenced better convergent and discriminant validity results than did the disruptive behavior disorders (DBDs) such as oppositional-defiant disorder (ODD) and conduct disorder (CD). Despite this finding, psychopathy scales nonetheless correlated with other forms of psychopathology at a higher rate than was expected, suggesting that comorbidity is high even when psychopathy is used as a classification scheme. Also, hierarchical multiple regression was used to determine whether psychopathy offered an improvement in the prediction of previous violent and nonviolent offenses. The results for the current study were mixed, with only the PCL-YV significantly predicting previous violent and nonviolent offenses beyond the DBDs. The findings indicate that psychopathy may offer incremental improvement over DBDs with regard to level of comorbidity and perhaps even prediction. However, simply extending the adult construct of psychopathy to youth without considering the array of psychopathology that may accompany adolescent psychopathy could be misleading.  相似文献   
40.
Online primary sources are a valuable resource for undergraduate students in religious studies courses. They provide firsthand, factual information about the beliefs and practices of religious traditions, movements, cults, and so on. In addition, they are readily and freely accessible online. Given their value as an information resource, undergraduate students need to be able to identify primary sources and understand how to use them in academic research. The purpose of this article is to describe activities for information literacy instruction that focus on primary sources in religious studies. These activities are intended as a resource for academic librarians who are teaching—or who plan to teach—undergraduate students how to identify and use primary sources.  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