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   5589篇
  免费   296篇
  国内免费   1篇
  2024年   13篇
  2023年   81篇
  2022年   64篇
  2021年   104篇
  2020年   146篇
  2019年   182篇
  2018年   262篇
  2017年   268篇
  2016年   266篇
  2015年   184篇
  2014年   192篇
  2013年   663篇
  2012年   400篇
  2011年   406篇
  2010年   230篇
  2009年   143篇
  2008年   322篇
  2007年   265篇
  2006年   236篇
  2005年   193篇
  2004年   180篇
  2003年   152篇
  2002年   116篇
  2001年   70篇
  2000年   86篇
  1999年   58篇
  1998年   36篇
  1997年   32篇
  1996年   27篇
  1995年   22篇
  1994年   14篇
  1993年   26篇
  1992年   25篇
  1991年   34篇
  1990年   40篇
  1989年   25篇
  1988年   31篇
  1987年   26篇
  1986年   25篇
  1985年   24篇
  1984年   26篇
  1983年   21篇
  1982年   14篇
  1979年   13篇
  1978年   14篇
  1977年   13篇
  1974年   11篇
  1971年   9篇
  1968年   8篇
  1966年   9篇
排序方式: 共有5886条查询结果,搜索用时 31 毫秒
151.
This study examined the reliability and validity of a 12-min. walking test for coronary heart disease patients. CHD patients (28 men, 18 women) were recruited out of 86 CHD patients of the Martini Hospital Groningen, The Netherlands. 46 CHD patients (age M=66.0 yr., SD=6.8) participated in the reliability study and 24 (age M=62.0 yr., SD=9.2) in the validity study. A test-retest analysis showed a satisfactory Bland-Altman plot and an intraclass coefficient of .98. The Pearson correlation between the score on the test and the VO2 peak was .77. This test gives a reliable and valid assessment of cardiorespiratory fitness of CHD patients.  相似文献   
152.
The purpose of this study was to examine the Body Mass Index of 180 female Spanish Olympic athletes (M age = 27.1 yr., SD = 5.9 yr.) who participate in presentation sports and nonpresentation sports, in comparison with 114 female nonathletes (M age = 20.7, SD = 1.5 yr.). Presentation sports athletes have a profile similar to that of a university student but by age with a lower Body Mass Index. In particular, rhythmic gymnasts have a lower weight and Body Mass Index than other athletes and nonathletes.  相似文献   
153.
On March 11, 2004, Al-Qaeda set off 10 bombs on several train routes in Madrid. 192 people were killed and 2,000 wounded. In this study, 1,179 questionnaires were administered Week 2 after the attacks to residents 18 years and over from the affected geographical areas. The questionnaire included items about sociodemographic variables and exposure to the attacks. Psychological effects were assessed as presence of acute stress and depressive symptomatology and functional impairment. 46.7% of the sample presented symptomatology of acute stress and 49.6% depressive symptoms. Among the symptoms of acute stress, the most frequent were re-experiencing (72.5%) and dissociative symptoms (71.8%). The chief predicting variables in symptomatology were being female, over 65 yr. old, and a habitual train user. The large number of affected people was refined with an item analysis and the consideration of severity of interference in psychosocial functioning.  相似文献   
154.
Confirmatory factor analysis examined the factor structure of DSM IV Attention Deficit Hyperactivity Disorder symptoms and analyzed the differences in informants' ratings of ADHD symptoms by children's age and sex. A sample of 1,018 Spanish school children, 574 girls and 444 boys, ages 4 to 12 years, was rated by teachers and parents. Confirmatory factor analysis showed a similar fit for the three-factor model of Inattention, Hyperactivity, and Impulsivity (teachers: CFI = .976, RMR = .041, % of total variance = 83.2; parents: CFI = .969, RMR = .037, % of total variance = 82.7) and for the two-factor model of Inattention and Hyperactivity Impulsivity (teachers: CFI = .958, RMR = .044, % of total variance = 79.3; parents: CFI = .961, RMR = .038, % of total variance, 79.9). The two-factor model was selected as a parsi monious representation of the teachers' and parents' ratings of ADHD symptoms. Analyses of variance indicated significant differences in teachers' and parents' mean ratings across sex and school grades of children.  相似文献   
155.
This study examined the dimensional structure of Tomás-Sábado and Gómez-Benito's Death Anxiety Inventory and Templer, et al.'s Death Depression Scale-Revised. The responses of 244 Spanish nurses to the Spanish forms of both scales were evaluated by means of a principal axis factor analysis with direct Oblimin rotation. Five significant factors were identified: Internally Generated Death Anxiety, Death Depression, Externally Generated Death Anxiety, Death Threat, and Death Sadness, accounting for 51.6% of the variance. The distribution of the factor loadings for the items of both scales on the five factors supported the discriminant validity of the constructs specific to each of the scales and justified their use in evaluating death anxiety and death depression independently.  相似文献   
156.
Sheehan's shortened form of Betts' Questionnaire Upon Mental Imagery is one of the most widely used inventories for measuring imaging. Participants were 562 undergraduate students (414 women and 148 men), with a mean age of 20.2 yr. In a principal components analysis followed by varimax orthogonal rotation for the Spanish version, eight factors were identified, six of which coincide with those of the original English version. Internal consistency was .92 (Cronbach alpha). Scores on the Betts Questionnaire Upon Mental Imagery correlated -.34 with those on the Gordon Test of Visual Imagery Control, .58 with those on the Vividness of Visual Imagery Questionnaire, and .02 with the Verbalizer-Visualizer Questionnaire.  相似文献   
157.
The rater agreement literature is complicated by the fact that it must accommodate at east two different properties of rating data: the number of raters (two versus more than two) and the rating scale level (nominal versus metric). While kappa statistics are most widely used for nominal scales, intraclass correlation coefficients have been preferred for metric scales. In this paper, we suggest a dispersion-weighted kappa framework for multiple raters that integrates some important agreement statistics by using familiar dispersion indices as weights for expressing disagreement. These weights are applied to ratings identifying cells in the traditional inter-judge contingency table. Novel agreement statistics can be obtained by applying less familiar indices of dispersion in the same wayThis revised article was published online in August 2005 with the PDF paginated correctly.  相似文献   
158.
We look at the problem of revising fuzzy belief bases, i.e., belief base revision in which both formulas in the base as well as revision-input formulas can come attached with varying degrees. Working within a very general framework for fuzzy logic which is able to capture certain types of uncertainty calculi as well as truth-functional fuzzy logics, we show how the idea of rational change from “crisp” base revision, as embodied by the idea of partial meet (base) revision, can be faithfully extended to revising fuzzy belief bases. We present and axiomatise an operation of partial meet fuzzy base revision and illustrate how the operation works in several important special instances of the framework. We also axiomatise the related operation of partial meet fuzzy base contraction.This paper is an extended version of a paper presented at the Nineteenth Conference on Uncertainty in Arti.cial Intelligence (UAI’03).  相似文献   
159.
160.
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