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   20216篇
  免费   242篇
  国内免费   26篇
教育   14065篇
科学研究   2435篇
各国文化   153篇
体育   1379篇
综合类   33篇
文化理论   318篇
信息传播   2101篇
  2022年   116篇
  2021年   189篇
  2020年   274篇
  2019年   393篇
  2018年   1199篇
  2017年   1221篇
  2016年   972篇
  2015年   399篇
  2014年   508篇
  2013年   2788篇
  2012年   563篇
  2011年   693篇
  2010年   646篇
  2009年   477篇
  2008年   534篇
  2007年   654篇
  2006年   330篇
  2005年   388篇
  2004年   428篇
  2003年   344篇
  2002年   293篇
  2001年   381篇
  2000年   404篇
  1999年   300篇
  1998年   189篇
  1997年   220篇
  1996年   219篇
  1995年   141篇
  1994年   158篇
  1993年   134篇
  1992年   236篇
  1991年   224篇
  1990年   238篇
  1989年   240篇
  1988年   217篇
  1987年   216篇
  1986年   200篇
  1985年   240篇
  1984年   185篇
  1983年   153篇
  1982年   154篇
  1981年   127篇
  1980年   127篇
  1979年   204篇
  1978年   158篇
  1977年   135篇
  1975年   106篇
  1974年   115篇
  1973年   104篇
  1971年   106篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
921.
Forty-nine previously sedentary or low active individuals aged 40-71 years were allocated to three groups. The long walking group participated in an 18-week walking programme which consisted of walks lasting 20-40 min; the repetitive short walking group completed walks of between 10 and 15 min, up to three times a day, with no less than 120 min between each walk; and the control group maintained their low level of activity. Both walking programmes began at a prescribed 60 min x week(-1), which increased steadily up to 200 min x week(-1) by week 12. During the study, the long walking group walked for an estimated 2514 min (139 min x week(-1)), expending an estimated 67.5 MJ (3.72 MJ x week(-1)) at an estimated 73% of their age-predicted maximum heart rate and 68% of their estimated VO2max. The repetitive short walking group walked for an estimated 2476 min (135 min x week(-1)), expending an estimated 58.5 MJ (3.17 MJ x week(-1)) at an estimated 71% of their age-predicted maximum heart rate and 65% of their estimated VO2max. The results showed a statistically significant reduction in heart rate during a standardized step test (pre- vs post-intervention) in both walking groups, indicating an improvement in aerobic fitness, although the control group showed a higher average heart rate during the post-intervention test, indicating reduced fitness. When compared with the male subjects pre-intervention, the females possessed more favourable levels of high-density lipoprotein (HDL) cholesterol (P< 0.001), apolipoprotein (apo) AI (P < 0.001) and ratios of total cholesterol:HDL cholesterol (P< 0.02) and low-density lipoprotein (LDL) cholesterol: HDL cholesterol (P< 0.02). Compared with the controls post-intervention, the walking groups showed no statistically significant changes in total cholesterol, LDL cholesterol, HDL cholesterol, apo AI, apo AII, apo B, or the ratios of total cholesterol: HDL cholesterol, LDL cholesterol: HDL cholesterol, apo AI: apo B or apo AI: apo AII (P > 0.05). Relative to the walking groups, factor XIIa increased in the control group (P < 0.05). We conclude that, although both walking programmes appeared to improve aerobic fitness, there was no evidence of improvements in the blood lipids or associated apolipoproteins of the walking groups. Further analysis indicated that this apparent lack of change may have been related to the subjects' relatively good pre-intervention blood lipid profiles, which restricted the potential for change. The implications of the observed changes in the coagulation/fibrinolytic factors remain unclear.  相似文献   
922.
923.
924.
925.
926.
927.
A survey of mathematics teaching practices in the first four years of the primary school examines teaching methods in relation to patterns of teaching behaviour. It shows how methods combine, how both the use of methods and teaching behaviour vary with school year and pupil ability, and how one method changed over a period of five years. Implications for method‐evaluation and observations on the teacher's reaction to age and ability differences are offered.  相似文献   
928.
929.
930.

Readers with young children may have noticed the occasional Spanish language vignettes appearing from time to time on Sesame Street, the popular public television program for pre‐schoolers. The following article describes the development and audience impact of a program designed to reach a Spanish‐American audience in a Texas city. The study is presented primarily as a guide for other programmers desiring to evaluate audience effects of such content. This article is a summary of a longer report done under an Office of Education subcontract to the Center for Communication Research at the University of Texas. Dr. Williams is Director of the Center and professor in the school of communications, while Diana Natalicio is now an assistant professor of linguistics at the University of Texas at El Paso after having completed her doctorate in linguistics at the Austin campus in 1970.  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