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   14501篇
  免费   172篇
  国内免费   8篇
教育   10595篇
科学研究   1247篇
各国文化   86篇
体育   1145篇
综合类   8篇
文化理论   90篇
信息传播   1510篇
  2021年   103篇
  2020年   163篇
  2019年   270篇
  2018年   370篇
  2017年   379篇
  2016年   348篇
  2015年   215篇
  2014年   295篇
  2013年   2712篇
  2012年   310篇
  2011年   379篇
  2010年   236篇
  2009年   229篇
  2008年   329篇
  2007年   243篇
  2006年   313篇
  2005年   207篇
  2004年   191篇
  2003年   186篇
  2002年   217篇
  2001年   323篇
  2000年   300篇
  1999年   270篇
  1998年   136篇
  1997年   164篇
  1996年   181篇
  1995年   183篇
  1994年   148篇
  1993年   165篇
  1992年   241篇
  1991年   216篇
  1990年   213篇
  1989年   246篇
  1988年   246篇
  1987年   209篇
  1986年   207篇
  1985年   218篇
  1984年   190篇
  1983年   234篇
  1982年   171篇
  1981年   162篇
  1980年   158篇
  1979年   232篇
  1978年   184篇
  1977年   167篇
  1976年   150篇
  1975年   129篇
  1974年   119篇
  1973年   125篇
  1971年   108篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
62.
This study examined the psychometric properties of a questionnaire developed with the guidance of the socialization model of child behaviour to understand modifiable correlates of toddlers’ physical activity and sedentary behaviour. Findings are based on 118 parents (33.7 ± 4.9 years; 86% female) of toddlers (19.3 ± 2.7 months; 48% female) from Edmonton, Canada in The Parents’ Role in Establishing healthy Physical activity and Sedentary behaviour habits study (PREPS). The PREPS questionnaire encompassed 21 variables across the constructs of the socialization model of child behaviour. Of the nine variables assessed for internal consistency reliability, eight had good (α ≥ 0.70) reliability. Of the 15 continuous variables assessed for 1-week test–retest reliability, 10 had moderate (intra-class correlation = 0.50–0.74) and 5 had good (intra-class correlation ≥ 0.75) reliability. Of the six categorical variables assessed for 1-week test–retest reliability, two had fair (К = 0.21–0.40), one had moderate (К = 0.41–0.60), one had substantial (К = 0.61–0.80), and two had almost perfect (К = 0.81–1.00) reliability. Of the 12 sedentary behaviour variables assessed for convergent validity, 7 were significantly correlated with children’s screen time, of which three were small (r ≤ 0.29), two were medium (r = 0.30–0.49), and two were large (r ≥ 0.50) effect sizes.  相似文献   
63.
This study investigated the impact of an open inquiry experience on elementary science methods students’ understanding of celestial motion as well as the methods developed by students to answer their own research questions. Pre/post interviews and assessments were used to measure change in participants’ understanding (N = 18). A qualitative approach was used to describe the nature of each participant’s investigation through an analysis of their science journal and poster presentations. A comparison of participants’ inquiry projects with the change in their understanding revealed that while most participants improved in both their area of inquiry and beyond, elementary science methods students may need more guidance to reach a full scientific understanding across all aspects of celestial motion.  相似文献   
64.
The main purpose of the present research was to check the possibility of measuring the feeling of “intuitive acceptance”, experienced by a subject when he offers an intuitive solution to a problem. It was postulated that two dimensions have to be considered and combined: The level of confidence and the degree of obviousness. Almost all the questions asked referred to the notion of infinity. The subjects were pupils belonging to grades 8 and 9. Three main categories of problematic situations have been identified:
  1. Problems which got high percentages of correct solutions and high levels of intuitive acceptance.
  2. Problems which got two types of contradictory solutions, each of them being accepted with moderate intuitiveness.
  3. Problems which got low frequencies of correct solutions and high frequencies of typical incorrect solutions, the second category presenting higher levels of intuitive acceptance than the first (counter-intuitive problematic situations).
  相似文献   
65.
66.
This study investigated the effects of a peer teaching procedure, combined with student letter-writing activities, on the acquisition and generalization of capitalization skills. Three students, aged 9 years, obtained instruction from peer partners that included (a) an introduction and review of capitalization rules, (b) feedback on each participant's previous capitalization work, and (c) guided and independent practice on sentences that required capitalization. All three students demonstrated acquisition of the capitalization rules after participating in the teaching sessions with one or two peer partners. In addition, there were increases in capitalization accuracy in participants' letters to peers who did not serve as teaching partners, thus demonstrating a measure of across-peer (stimulus) generalization. Mixed results were obtained on a response generalization task (sentence writing). Finally, sentencing-writing activities also showed that two of the peer partners substantially improved their use of capitalization skills as a result of teaching the target students.  相似文献   
67.
We describe an assessment of the collective impact of 35 grants that the Howard Hughes Medical Institute (HHMI) made to biomedical research institutions in 1999 to support precollege science education outreach programs. Data collected from funded institutions were compared with data from a control group of institutions that had advanced to the last stage of review but had not been funded. The survey instrument and the results reveal outcomes and impacts that HHMI considers relevant for these programs. The following attributes are considered: ability to secure additional, non-HHMI funding; institution buy-in as measured by gains in dedicated space and staff; enhancement of the program director''s career; number and adoption of educational products developed; number of related publications and awards; percentage of programs for which teachers received course credit; increase in science content knowledge; and increase in student motivation to study science.  相似文献   
68.
To elucidate a higher rate of premature cardiovascular disease (CVD) in Asian Indian descendants (Roma) in Slovakia, we investigated frequency distribution, correlates and relationship of lipoprotein(a) [Lp(a)] to family CVD risk factors in Roma children and their Caucasian neighbors. The study sample consisted of 607 healthy children aged 7–18 years (55% Roma, 48% male) as part of the biracial (Roma–Caucasian) Slovak Lipid Community Study. Overall, frequency distribution data of Lp(a) were highly skewed to low concentrations, with markedly higher Lp(a) levels in Roma than in Caucasian children (median and range, mg/dL: 14.5; 0–159.2 vs 6.2; 0–112.3, P < 0.001), regardless of age and gender. Lp(a) was positively correlated with apo B (0.159, P = 0.004) in Roma, and LDL cholesterol (0.170, P = 0.005) in Caucasian children. In addition, daily income of the family was negatively related with Lp(a) in Roma (−0.134, P = 0.036) while positively in Caucasians (0.136, P = 0.047). For both race groups, no significant association was found between Lp(a) and age, body mass index, mean arterial pressure, smoking, and physical activity. Also, no significant relationships were examined between serum Lp(a) levels >30 mg/dL in children and family CVD risk factors, except for diabetes mellitus in parents of Caucasian origin (OR 4.46; 95%CI: 1.23–16.20). In a multivariate analysis, daily income, LDL cholesterol or apo B explained ~7% of the variance of Lp(a). This study suggests a significantly higher serum Lp(a) levels in Roma than in Caucasian children and a small effect, in general, of relevant CVD risk factors on the variation of Lp(a) levels in childhood.  相似文献   
69.
70.
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