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   27081篇
  免费   336篇
  国内免费   341篇
教育   20172篇
科学研究   2499篇
各国文化   9篇
体育   2056篇
综合类   1573篇
文化理论   13篇
信息传播   1436篇
  2024年   8篇
  2023年   66篇
  2022年   202篇
  2021年   484篇
  2020年   610篇
  2019年   550篇
  2018年   376篇
  2017年   390篇
  2016年   359篇
  2015年   703篇
  2014年   1613篇
  2013年   1649篇
  2012年   2098篇
  2011年   2151篇
  2010年   1399篇
  2009年   1402篇
  2008年   1491篇
  2007年   1912篇
  2006年   1805篇
  2005年   1577篇
  2004年   1505篇
  2003年   1486篇
  2002年   1357篇
  2001年   1185篇
  2000年   673篇
  1999年   256篇
  1998年   129篇
  1997年   88篇
  1996年   60篇
  1995年   31篇
  1994年   15篇
  1993年   21篇
  1992年   10篇
  1991年   4篇
  1990年   11篇
  1989年   5篇
  1987年   1篇
  1985年   20篇
  1984年   6篇
  1983年   14篇
  1982年   11篇
  1981年   13篇
  1980年   4篇
  1979年   2篇
  1978年   3篇
  1977年   2篇
  1957年   1篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
Using PISA and PIAAC data from twelve OECD countries, we examine the gap in cognitive skills among immigrants and natives and evaluate how those differences have evolved over time. We also consider how demographics, family background and school quality explain the development of cognitive skills of young people with immigrant backgrounds. The results show, first, that some convergence in skills occurs between second-generation immigrants and natives over time. Second, demographics, family background and school quality variables all contribute to the achievement gaps across different groups.  相似文献   
2.
[目的/意义]研究方法在学术研究中发挥着至关重要的作用。确认图书馆情报学领域主要的研究方法,并对它们进行了解熟悉,以在开展研究时能合理选择、灵活使用,确保研究质量。[方法/过程]对近2 000篇图书馆情报学领域的研究文献以及相关研究方法论文进行内容分析,在此基础上对研究方法的类分命名、图书馆情报学界主要的研究方法的确定、特点和使用注意事项进行介绍和讨论。[结果/结论]研究方法应以数据收集法而不是数据分析法命名。图书馆情报学领域常用的研究方法包括实验法、问卷法、理论研讨法、内容分析法、访谈法和书目计量法,每种方法都有各自的特点。因而在选择使用时,既应根据具体研究课题及研究方法之特性,也要考虑使用注意事项,并尽量在同一研究中采用两种或更多的方法,以扬长避短,更有效地展开研究。  相似文献   
3.
In addition to money or other compensation, other motives for selling sex may be important in a welfare country such as Sweden. The aim of this study was to carry out an exploratory investigation of adolescents’ motives for selling sex in a population-based survey in Sweden. A total of 5839 adolescents from the third year of Swedish high school, mean age 18.0 years, participated in the study. The response rate was 59.7% and 51 students (0.9%) reported having sold sex. Exploratory factor analysis and hierarchical cluster analysis were used to identify groups of adolescents according to underlying motives for selling sex. Further analyses were carried out for characteristics of selling sex and risk factors. Three groups of adolescents were categorized according to their motives for selling sex: Adolescents reporting; 1) Emotional reasons, being at a greater risk of sexual abuse, using sex as a means of self-injury and having a non-heterosexual orientation. 2) Material but no Emotional reasons, who more often receive money as compensation and selling sex to a person over 25 years of age, and 3) Pleasure or no underlying motive for selling sex reported, who were mostly heterosexual males selling sex to a person under 25 years of age, the buyer was not known from the Internet, the reward was seldom money and this group was less exposed to penetrative sexual abuse or using sex as a means of self-injury. In conclusion, adolescents selling sex are a heterogeneous group in regard to underlying motives.  相似文献   
4.
Child discipline is a central component of parent-child interactions. Evidence suggests corporal discipline impairs children’s physical, cognitive, and socioemotional development and compromises their future chances, especially since it is more frequently used against at-risk children. Using geocoded data for 1209 children under the age of five and their mothers, this study analyses the relation between the occurrence of crimes in close proximity to households in four major urban municipalities of Colombia and a particularly violent corporal discipline practice: hitting children with objects. Results indicate that exposure to violent crimes, such as homicides and personal injuries, predicts a higher probability of hitting children with objects, even after controlling for a set of individual, family, and neighborhood characteristics. Sensitivity analyses suggest violent crimes are not related to other discipline methods, and less threatening crimes, such as robbery and drug trafficking, are not associated with hitting children with objects. These findings suggest households’ walls are permeable, and outside threats may interfere with families’ dynamics and well-being. Future directions and implications are discussed.  相似文献   
5.
In this work, we present the first quality flaw prediction study for articles containing the two most frequent verifiability flaws in Spanish Wikipedia: articles which do not cite any references or sources at all (denominated Unreferenced) and articles that need additional citations for verification (so-called Refimprove). Based on the underlying characteristics of each flaw, different state-of-the-art approaches were evaluated. For articles not citing any references, a well-established rule-based approach was evaluated and interesting findings show that some of them suffer from Refimprove flaw instead. Likewise, for articles that need additional citations for verification, the well-known PU learning and one-class classification approaches were evaluated. Besides, new methods were compared and a new feature was also proposed to model this latter flaw. The results showed that new methods such as under-bagged decision trees with sum or majority voting rules, biased-SVM, and centroid-based balanced SVM, perform best in comparison with the ones previously published.  相似文献   
6.
BackgroundMaltreated youth are at an elevated risk for the development of problem behaviors. Coping with the death of a family member or close friend during adolescence, referred to as bereavement, is a stressful event that could potentiate risk linked to maltreatment. However, developmental research suggests that youth adjustment is a product of multiple risk and protective factors. Although maltreated youth who experience loss may be particularly vulnerable to behavior problems, personal and contextual factors may attenuate or exacerbate youths’ risk for internalizing and externalizing psychopathology.ObjectiveThe overarching goal of this study is to examine individual, family, and community-level protective factors for maltreated youth who experience bereavement. Specifically, we aim to examine the effect of age 12 bereavement on age 16 internalizing and externalizing psychopathology, and to investigate the moderating role of multi-level protective factors at ages 14 and 16.MethodsThe study consisted of a sample of 800 youth (52.4% female, 45.1% African-American) drawn from the Longitudinal Studies of Child Abuse and Neglect (LONGSCAN), collected from 1998 to 2011.ResultsMaltreated youth who experienced significant loss were at increased risk for externalizing symptoms, compared to non-bereaved maltreated youth (β = 0.085, p < .05). Individual future orientation (β = 0.103, p < .05) family future orientation (β = −0.120, p < .05), parental monitoring (β = −0.123, p< .01), and neighborhood collective efficacy (β = −0.126, p < .01) each significantly moderated the association between bereavement and externalizing symptoms.ConclusionsThese results have implications for future interventions aimed towards reducing problem behaviors in adolescents with a history of child maltreatment and who experience bereavement.  相似文献   
7.
高校扩招后体育教学质量下降的原因分析及对策   总被引:1,自引:0,他引:1  
运用综合研究方法,对扩大招生后广西10所高校体育教学情况进行了问卷调查,并对调查结果进行相关分析。发现影响体育教学质量的主要因素为运动场地、设施;师资力量;生源质量;教学管理水平。提出:加大体育经费投入,改善运动场地、设施;加强体育师资的建设与管理;因材施教,实施学分制;提高体育教学的管理水平。制定科学的教学质量评估体系,是稳定和提高体育教学质量的重要举措。  相似文献   
8.
阿克洛夫模型与图书馆馆员素质建设   总被引:3,自引:0,他引:3  
为适应信息社会的需要,馆员素质建设不容忽视。章以图书馆馆员素质之间的差异为前提,通过应用阿克洛夫模型对图书馆人员素质低下及人才流失的现象进行分析,提出加强馆员素质建设的方法。  相似文献   
9.
曹莉娟 《体育科技》2003,24(3):66-70
体育课教学是高等学校体育工作的核心。教学质量的好坏直接影响学生的体质。但是 ,现行的班级体育授课制仍然是沿袭以智力、高考分数为核心 ,方便文化课教学的编班制进行体育课教学 ,这无疑影响学生体质的发展和终身体育思想的形成 ,而且给体育课教学带来许多困难。因此 ,从发展学生体质和培养终身锻炼习惯的实际需要出发 ,打破单纯按智力、分数的分班制是当前高校体育教学工作中亟待解决的问题。  相似文献   
10.
文章论述高校图书馆利用地方资源服务人文素质教育的可行性及重要意义,井探讨了服务原则和服务内容。  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