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   668篇
  免费   21篇
教育   493篇
科学研究   27篇
各国文化   7篇
体育   61篇
文化理论   6篇
信息传播   95篇
  2023年   4篇
  2022年   6篇
  2021年   10篇
  2020年   30篇
  2019年   40篇
  2018年   51篇
  2017年   61篇
  2016年   35篇
  2015年   27篇
  2014年   34篇
  2013年   162篇
  2012年   20篇
  2011年   7篇
  2010年   11篇
  2009年   13篇
  2008年   8篇
  2007年   11篇
  2006年   15篇
  2005年   10篇
  2004年   9篇
  2003年   6篇
  2002年   5篇
  2001年   5篇
  2000年   9篇
  1999年   7篇
  1998年   8篇
  1997年   4篇
  1996年   2篇
  1995年   2篇
  1994年   3篇
  1993年   2篇
  1992年   3篇
  1991年   5篇
  1990年   2篇
  1989年   7篇
  1987年   4篇
  1986年   5篇
  1985年   2篇
  1984年   2篇
  1983年   3篇
  1982年   4篇
  1981年   4篇
  1980年   3篇
  1979年   4篇
  1978年   5篇
  1977年   2篇
  1970年   2篇
  1912年   3篇
  1850年   1篇
  1841年   1篇
排序方式: 共有689条查询结果,搜索用时 999 毫秒
1.
2.
3.
Genetics Home Reference is a free, online resource created and maintained by the National Library of Medicine. It is designed to provide genetic information to a wide variety of audiences, particularly the general public. The site consists of original information and links to other curated resources.  相似文献   
4.
Oh and LaRose (2016) contended that problem severity and channel publicness shape support seekers’ goals, time spent composing messages, and the sophistication of those messages. The current study seeks to replicate and extend Oh and LaRose’s study to produce a more accurate understanding of the factors that influence the sophistication of support-seeking messages online. Support seekers’ goals varied according to the severity of a stressor and the publicness of a channel, and the amount of time people spent composing a message influenced its sophistication. We extend the original study by examining associations that were not initially tested. Time spent composing messages mediated the influence of problem severity on the quality of people’s messages, and this effect was moderated by channel publicness.  相似文献   
5.
ABSTRACT

The aims of the present study were to provide an in-depth comparison of inter-limb asymmetry and determine how consistently asymmetry favours the same limb during different vertical jump tests. Eighteen elite female under-17 soccer players conducted unilateral squat jumps (SJ), countermovement jumps (CMJ) and drop jumps (DJ) on a portable force platform, with jump height, peak force, concentric impulse and peak power as common metrics across tests. For the magnitude of asymmetry, concentric impulse was significantly greater during the SJ test compared to CMJ (p = 0.019) and DJ (p = 0.003). No other significant differences in magnitude were present. For the direction of asymmetry, Kappa coefficients revealed fair to substantial levels of agreement between the SJ and CMJ (Kappa = 0.35 to 0.61) tests, but only slight to fair levels of agreement between the SJ and DJ (Kappa = ?0.26 to 0.18) and CMJ and DJ (Kappa = ?0.13 to 0.26) tests. These results highlight that the mean asymmetry value may be a poor indicator of true variability of between-limb differences in healthy athletes. The direction of asymmetry may provide a useful monitoring tool for practitioners in healthy athletes, when no obvious between-limb deficit exists.  相似文献   
6.
Abstract

Maternal dietary habits influence maternal and foetal health, representing a pathway for intervention to maximise pregnancy outcomes. Advice on energy intake is provided on a trimester basis, with no additional calories required in the first trimester and an additional 340?kcal?d?1 and 452?kcal?d?1 needed for the second and third trimesters. Energy intake depends on pre-gravid body mass index (BMI); underweight women are recommended an increase of 150, 200 and 300?kcal?d?1 during the first, second and third trimester, normal weight women an increase of 0, 350 and 500?kcal?d?1 and obese women an increase of 0, 450 and 350?kcal?day?1. The recommendations for carbohydrate and protein intake are 175?g?d?1 and 0.88–1.1?g?kgBM?d?1, with no change to fat intake. The number of pre-gravid obese women is rising; therefore, we need to regulate weight in women of childbearing age and limit gestational weight gain to within the recommended ranges [overweight women 6.8–11.3?kg and obese women 5.0–9.1?kg]. This can be achieved using nutritional interventions, as dietary changes have been shown to help with gestational weight management. As pregnancy has been identified as a risk factor for the development of obesity, normal weight women should gain 11.5–16.0?kg during pregnancy. While some research has shown that dietary interventions help to regulate gestational weight gain and promote postpartum weight loss to some extent, future research is needed to provide safe and effective guidelines to maximise these effects, while benefitting maternal and foetal health.  相似文献   
7.
8.
This paper reports on efforts aimed toward the development of more effective procedures for identifying mothers who are at elevated risk for problems in parenting. We present data from two independent samples of known maladaptors and corresponding comparison mothers and report on our attempts to cross-validate a promising screening instrument composed of items that index social support and parenting attitudes. The resultant 20-item scale correctly identified over 90% of maladaptive and comparison mothers. When this scale was cross-validated on a second independent sample of maladaptors and comparison mothers, it was again almost 90% accurate. Issues concerning the field application of this promising instrument are discussed and its possible limitations are considered.  相似文献   
9.
Selective universities regularly employ policies that favor children of alumni (known as legacies) in undergraduate admissions. Since alumni from selective colleges and universities historically have been disproportionately white, admissions policies that favor legacies have disproportionately benefited white students. For this reason, legacy policies lead to additional costs in terms of reductions in racial diversity. As larger numbers of minority students graduate from colleges and universities and have children, however, the potential pool of legacy applicants will change markedly in racial composition. This analysis begins with a review of the history and objectives of the preference for children of alumni in undergraduate admissions. We then consider the specific case of the University of Virginia and employ demographic techniques to predict the racial composition of the pool of potential legacy applicants to the university. Significant changes in the racial composition of classes that graduated from the University of Virginia from the late 1960s through the 1970s foreshadow similar changes in the characteristics of alumni children maturing through the next two decades.  相似文献   
10.
High turnover rates of early care and education teachers reduce the quality of education; unsatisfied teachers, suffering from stress or emotional exhaustion, are less equipped to promote children’s development and more likely to leave the classroom. We used data from a national survey of US early childhood educators (n?=?1129) to examine associations between teachers’ working conditions, well-being, and motivation with professional commitment and turnover intentions to move, leave, or remain. Multiple regression analyses revealed that more intrinsically motivated teachers were more likely to report intentions to move over leave, emotionally exhausted teachers were more likely to report intentions to leave, and lower teacher-reported working conditions predicted intentions to move or leave the field over staying. The results suggest that teachers’ well-being and perceived working conditions relate with their intentions to remain at their job or within the field and to their commitment to the profession.  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