全文获取类型
收费全文 | 43174篇 |
免费 | 588篇 |
国内免费 | 28篇 |
专业分类
教育 | 30767篇 |
科学研究 | 3689篇 |
各国文化 | 462篇 |
体育 | 3710篇 |
综合类 | 18篇 |
文化理论 | 365篇 |
信息传播 | 4779篇 |
出版年
2021年 | 444篇 |
2020年 | 682篇 |
2019年 | 1059篇 |
2018年 | 1423篇 |
2017年 | 1382篇 |
2016年 | 1255篇 |
2015年 | 761篇 |
2014年 | 1102篇 |
2013年 | 8246篇 |
2012年 | 1018篇 |
2011年 | 1082篇 |
2010年 | 822篇 |
2009年 | 869篇 |
2008年 | 947篇 |
2007年 | 874篇 |
2006年 | 792篇 |
2005年 | 709篇 |
2004年 | 710篇 |
2003年 | 617篇 |
2002年 | 634篇 |
2001年 | 811篇 |
2000年 | 812篇 |
1999年 | 705篇 |
1998年 | 437篇 |
1997年 | 437篇 |
1996年 | 512篇 |
1995年 | 456篇 |
1994年 | 412篇 |
1993年 | 396篇 |
1992年 | 587篇 |
1991年 | 595篇 |
1990年 | 578篇 |
1989年 | 607篇 |
1988年 | 539篇 |
1987年 | 564篇 |
1986年 | 538篇 |
1985年 | 612篇 |
1984年 | 497篇 |
1983年 | 480篇 |
1982年 | 403篇 |
1981年 | 379篇 |
1980年 | 390篇 |
1979年 | 558篇 |
1978年 | 408篇 |
1977年 | 375篇 |
1976年 | 329篇 |
1975年 | 295篇 |
1974年 | 309篇 |
1973年 | 283篇 |
1971年 | 296篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
31.
This investigation was undertaken in an effort to establish physiological characteristics of soccer players and to relate them to positional roles. A total of 135 footballers (age 24.4 +/- 4.6 years) were assessed for body mass, % body fat, haemoglobin, maximal oxygen uptake (VO2 max), leg power, anaerobic capacity and speed prior to an English league season. The sample included 13 goalkeepers, 22 full-backs, 24 centre-backs, 35 midfield players and 41 forwards. The goalkeepers were significantly heavier (86.1 +/- 5.5 kg; P < 0.01) than all groups except the centre-backs, had significantly higher estimated body fat percentages than centre-backs, forwards, midfield players (P < 0.01) or full-backs (P < 0.05), significantly lower estimated VO2 max values (56.4 +/- 3.9 ml kg-1 min-1; P < 0.01) and were slowest over 60 m (12.71 +/- 0.42 s). The midfield players had the highest predicted VO2 max values (61.4 +/- 3.4 ml kg-1 min-1), this being significantly greater (P < 0.05) than for the centre-backs. The forwards were the fastest group over 60 m (12.19 +/- 0.30 s), being significantly quicker than goalkeepers or centre-backs (P < 0.01) and full-backs (P < 0.05). Anaerobic power, as well as knee extensor torques (corrected for body mass) and extensor-flexor ratios, were similar between groups. No difference in estimated body fat percentage was observed between any of the outfield players, and haemoglobin concentrations were similar among players of all positions.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
32.
33.
34.
35.
36.
GARRETT J. McAULIFFE 《Counselor Education & Supervision》1992,31(3):163-174
A case presentation method of group supervision, as practiced at a community college, is described. Developmental principles underlying this approach are presented. 相似文献
37.
38.
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
39.
40.
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