全文获取类型
收费全文 | 51645篇 |
免费 | 766篇 |
国内免费 | 37篇 |
专业分类
教育 | 36557篇 |
科学研究 | 4878篇 |
各国文化 | 600篇 |
体育 | 4109篇 |
综合类 | 23篇 |
文化理论 | 451篇 |
信息传播 | 5830篇 |
出版年
2021年 | 500篇 |
2020年 | 784篇 |
2019年 | 1209篇 |
2018年 | 1604篇 |
2017年 | 1594篇 |
2016年 | 1433篇 |
2015年 | 879篇 |
2014年 | 1289篇 |
2013年 | 9987篇 |
2012年 | 1190篇 |
2011年 | 1246篇 |
2010年 | 958篇 |
2009年 | 1023篇 |
2008年 | 1105篇 |
2007年 | 1024篇 |
2006年 | 946篇 |
2005年 | 843篇 |
2004年 | 821篇 |
2003年 | 723篇 |
2002年 | 728篇 |
2001年 | 910篇 |
2000年 | 907篇 |
1999年 | 810篇 |
1998年 | 513篇 |
1997年 | 501篇 |
1996年 | 576篇 |
1995年 | 512篇 |
1994年 | 490篇 |
1993年 | 482篇 |
1992年 | 687篇 |
1991年 | 708篇 |
1990年 | 683篇 |
1989年 | 717篇 |
1988年 | 631篇 |
1987年 | 648篇 |
1986年 | 637篇 |
1985年 | 718篇 |
1984年 | 614篇 |
1983年 | 586篇 |
1982年 | 500篇 |
1981年 | 481篇 |
1980年 | 476篇 |
1979年 | 664篇 |
1978年 | 530篇 |
1977年 | 459篇 |
1976年 | 409篇 |
1975年 | 372篇 |
1974年 | 377篇 |
1973年 | 360篇 |
1971年 | 355篇 |
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
81.
Medicine has made increasing use of meta-analysis, largely as a quantitative procedure for combining results of clinical trials. Meta-analysis begins with a comprehensive review of the literature. The next step is a systematic analysis of the quality and content of each study. Finally, results are combined statistically and conclusions are drawn from this new overview of the data. This paper presents a brief historical perspective on the use of meta-analysis in medicine with emphasis on the medical library. The authors conclude that in the future, medical librarians will play a significant role in the application of this useful technique. 相似文献
82.
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
83.
Chaos theory, informational needs, and natural disasters 总被引:2,自引:0,他引:2
Timothy L. Sellnow Matthew W. Seeger Robert R. Ulmer 《Journal of Applied Communication Research》2002,30(4):269-292
This study applies chaos theory to a system-wide analysis of crisis communication in a natural disaster. Specifically, we analyze crisis communication during the 1997 Red River Valley flood in Minnesota and North Dakota. This flood, among the worst in modern American history, consumed entire metropolitan areas, displacing thousands of people. The conditions and decisions leading to the disaster, and the subsequent reactions are retraced. Communication related to river crest predictions (fractals), the shock at the magnitude of the crisis (cosmology episode), novel forms of reorganizing (self-organization), and agencies that aided in establishing a renewed order (strange attractors) are evaluated. Ultimately, we argue that preexisting sensemaking structures favoring rationalized, traditional views of a complex system led officials to make inappropriately unequivocal predictions and ultimately diminished the effectiveness of the region's crisis communication and planning. 相似文献
84.
85.
John Marshall is best remembered asthe first resident director of the RockefellerFoundation's Study and Conference Center atBellagio. Yet, his influence on knowledge,thought, and practice rivalled that of any ofhis contemporaries at the Rockefeller. Thispaper describes how he `went about hisbusiness' as a Foundation officer, and examineshis contribution to the creation of atransatlantic community of like-mindedtheorists and practitioners of communications. 相似文献
86.
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
87.
88.
89.
90.
Annemarie de Knecht-van Eekelen Steven Bakker Gerben van Lent 《Educational Measurement》2001,20(3):33-35
This is Part III of a three part series describing the consultancy and training demands that are encountered in technical assistance projects in Central and Eastern Europe. Part I dealt with strategic issues for a successful delivery of "Western Technical Assistance to Eastern Needs." Part II highlighted project management and co-operation aspects in delivering support to the Romanian Assessment and Examination Service. In this part, we address training of Polish subject experts who were preparing to take on responsibility for a decentralized and strongly innovative final exam, the Matura. 相似文献