全文获取类型
收费全文 | 53214篇 |
免费 | 759篇 |
国内免费 | 162篇 |
专业分类
教育 | 37838篇 |
科学研究 | 5298篇 |
各国文化 | 520篇 |
体育 | 4014篇 |
综合类 | 55篇 |
文化理论 | 443篇 |
信息传播 | 5967篇 |
出版年
2022年 | 341篇 |
2021年 | 506篇 |
2020年 | 828篇 |
2019年 | 1233篇 |
2018年 | 1668篇 |
2017年 | 1701篇 |
2016年 | 1590篇 |
2015年 | 939篇 |
2014年 | 1335篇 |
2013年 | 10075篇 |
2012年 | 1307篇 |
2011年 | 1396篇 |
2010年 | 1028篇 |
2009年 | 1030篇 |
2008年 | 1158篇 |
2007年 | 1071篇 |
2006年 | 989篇 |
2005年 | 945篇 |
2004年 | 870篇 |
2003年 | 821篇 |
2002年 | 853篇 |
2001年 | 959篇 |
2000年 | 892篇 |
1999年 | 862篇 |
1998年 | 491篇 |
1997年 | 522篇 |
1996年 | 607篇 |
1995年 | 543篇 |
1994年 | 464篇 |
1993年 | 477篇 |
1992年 | 722篇 |
1991年 | 696篇 |
1990年 | 733篇 |
1989年 | 732篇 |
1988年 | 651篇 |
1987年 | 652篇 |
1986年 | 616篇 |
1985年 | 743篇 |
1984年 | 621篇 |
1983年 | 585篇 |
1982年 | 513篇 |
1981年 | 491篇 |
1980年 | 433篇 |
1979年 | 634篇 |
1978年 | 516篇 |
1977年 | 477篇 |
1976年 | 410篇 |
1975年 | 354篇 |
1974年 | 370篇 |
1973年 | 360篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.
42.
43.
D A Sedlock 《Research quarterly for exercise and sport》1991,62(2):213-216
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
44.
45.
46.
The purpose of this investigation was to describe the morphological parameters that characterize elite age group divers. Comparisons are made to normative age group data from the Coquitlam Growth Study and the constancy of important characteristics from age group to age group is examined. Data were collected on 27 male and 28 female elite divers who participated in the 1990 North American Age Group Diving Championships. Body build, body composition and skinfold corrected diameters were determined from 36 anthropometric parameters and analysed by ANOVA, t-test and Phantom z-scores procedures. All age groups except the 14- to 15-year-old males were significantly (P < or = 0.05) shorter than their norms but recorded higher androgyny index values. The estimated relative muscle mass increased significantly (P < or = 0.05) with age for males at all ages (40.8-46.3%). The 16- to 18-year-old females had a significantly (P < or = 0.05) larger relative muscle component compared to the younger age groups (40.1-38.4%). When normalized for height, active tissue development of the extremities was comparable between the sexes except in the forearm. The results indicate that at all age levels short stature is an important characteristic for divers. Analysis of regional active tissue development provides further insight into sport-specific prerequisites for success at elite levels. 相似文献
47.
48.
This article is a preliminary analysis of the first few years of the Computer Matching and Privacy Protection Act of 1988 (CMPPA). The act requires Federal agencies to establish Data Integrity Boards (DIBs) with responsibility to approve written agreements for computer matches in which their agencies are involved. Information for this analysis was collected from the annual reports on computer matching submitted by agencies to the Office of Management and Budget (OMB) for 1990 and 1991 and from 108 matching agreements. The secretaries of several DIBs were also interviewed. The effectiveness of DIBs and matching agreements are analyzed using McCubbins and Schwartz's distinction between “police-patrol” and “fire- alarm” oversight. The article concludes that more active and direct oversight, which would occur through an independent data protection or privacy board, is necessary. 相似文献
49.
50.