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   41531篇
  免费   718篇
  国内免费   43篇
教育   29852篇
科学研究   3669篇
各国文化   415篇
体育   3190篇
综合类   46篇
文化理论   340篇
信息传播   4780篇
  2022年   279篇
  2021年   445篇
  2020年   680篇
  2019年   1011篇
  2018年   1387篇
  2017年   1434篇
  2016年   1299篇
  2015年   768篇
  2014年   1128篇
  2013年   8006篇
  2012年   1087篇
  2011年   1170篇
  2010年   865篇
  2009年   863篇
  2008年   978篇
  2007年   873篇
  2006年   788篇
  2005年   732篇
  2004年   684篇
  2003年   620篇
  2002年   670篇
  2001年   800篇
  2000年   707篇
  1999年   688篇
  1998年   377篇
  1997年   406篇
  1996年   456篇
  1995年   408篇
  1994年   368篇
  1993年   365篇
  1992年   575篇
  1991年   542篇
  1990年   566篇
  1989年   550篇
  1988年   499篇
  1987年   495篇
  1986年   462篇
  1985年   570篇
  1984年   456篇
  1983年   430篇
  1982年   371篇
  1981年   350篇
  1980年   311篇
  1979年   453篇
  1978年   362篇
  1977年   334篇
  1976年   290篇
  1975年   252篇
  1974年   255篇
  1973年   253篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
52.
53.
Ordinary markets allow parties, not the state, to value property and projects. But they do not account for subjective value in such traditional contexts as condemnation. An awareness of these nonmarket values helps overcome any categorical opposition to the use of the contingent valuation method (CVM) to value cultural and environmental resources. But accurate CVM should measure all values, positive or negative, tononowners; it should apply generally to any substitute projects; and it should seek to account for diminishing marginal value of additional resource units. CVM should be used only to aggregate nonmarket preferences, not to skew the political debate to cultural or environmental objectives.  相似文献   
54.
The purpose of this study was to determine test-retest reliability for the 1-mile, 3/4-mile, and 1/2-mile distance run/alk tests for children in Grades K-4. Fifty-one intact physical education classes were randomly assigned to one of the three distance run conditions. A total of 1,229 (621 boys, 608 girls) completed the test-retests in the fall (October), with 1,050 of these students (543 boys, 507 girls) repeating the tests in the spring (May). Results indicated that the 1-mile run/walk distance, as recommended for young children in most national test batteries, has acceptable intraclass reliability (.83 less than R less than .90) for both boys and girls in Grades 3 and 4, has minimal (fall) to acceptable (spring) reliability for Grade 2 students (.70 less than R less than .83), but is not reliable for children in Grades K and 1 (.34 less than R less than .56). The 1/2 mile was the only distance meeting minimal reliability standards for boys and girls in Grades K and 1 (.73 less than R less than .82). Results also indicated that reliability estimates remained fairly stable across gender and age groups from the fall to spring testing periods, with the exception of the noticeably improved values for Grade 2 students on the 1-mile run/walk test. Criterion-referenced reliability (P, percent agreement) was also estimated relative to Physical Best and Fitnessgram run/walk standards. Reliability coefficients for all age group standards were acceptable to high (.70 less than P less than .95), except for Fitnessgram standards for 5-year-old girls on the 1-mile test for both fall and spring and for 6-year-old boys and girls on the 1-mile test administered in the spring.  相似文献   
55.
This article reviews the literature pertaining to the written composing ability of students with learning disabilities that was published primarily in the decade from 1980 to 1990. The papers included are either reports of research or discussions of instructional procedures that are based on research. The topics addressed include story composition, expository writing, training/intervention research, and rationales/procedures for instruction.  相似文献   
56.
57.
This study was designed to examine the magnitude and duration of excess postexercise oxygen consumption (EPOC) following upper body exercise, using lower body exercise for comparison. On separate days and in a counterbalanced order, eight subjects (four male and four female) performed a 20-min exercise at 60% of mode-specific peak oxygen uptake (VO2) using an arm crank and cycle ergometer. Prior to each exercise, baseline VO2 and heart rate (HR) were measured during the final 15 min of a 45-min seated rest. VO2 and HR were measured continuously during the postexercise period until baseline VO2 was reestablished. No significant difference between the two experimental conditions was found for magnitude of EPOC (t [7] = 0.69, p greater than .05). Mean (+/- SD) values were 9.2 +/- 3.3 and 10.4 +/- 5.8 kcal for the arm crank and cycle ergometer exercises, respectively. Duration of EPOC was relatively short and not significantly different (t [7] = 0.24, p greater than .05) between the upper body (22.9 +/- 13.7 min) and lower body (24.2 +/- 19.4 min) exercises. Within the framework of the chosen exercise conditions, these results suggest EPOC may be related primarily to the relative metabolic rate of the active musculature, as opposed to the absolute exercise VO2 or quantity of active muscle mass associated with these two types of exercise.  相似文献   
58.
59.
60.
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