全文获取类型
收费全文 | 3518篇 |
免费 | 77篇 |
国内免费 | 6篇 |
专业分类
教育 | 2635篇 |
科学研究 | 180篇 |
各国文化 | 29篇 |
体育 | 497篇 |
综合类 | 4篇 |
文化理论 | 81篇 |
信息传播 | 175篇 |
出版年
2023年 | 34篇 |
2022年 | 55篇 |
2021年 | 76篇 |
2020年 | 131篇 |
2019年 | 205篇 |
2018年 | 262篇 |
2017年 | 259篇 |
2016年 | 208篇 |
2015年 | 137篇 |
2014年 | 123篇 |
2013年 | 709篇 |
2012年 | 133篇 |
2011年 | 93篇 |
2010年 | 90篇 |
2009年 | 91篇 |
2008年 | 85篇 |
2007年 | 74篇 |
2006年 | 64篇 |
2005年 | 51篇 |
2004年 | 37篇 |
2003年 | 48篇 |
2002年 | 113篇 |
2001年 | 32篇 |
2000年 | 31篇 |
1999年 | 31篇 |
1998年 | 28篇 |
1997年 | 24篇 |
1996年 | 31篇 |
1995年 | 26篇 |
1994年 | 25篇 |
1993年 | 19篇 |
1992年 | 16篇 |
1991年 | 18篇 |
1990年 | 16篇 |
1989年 | 23篇 |
1988年 | 24篇 |
1987年 | 18篇 |
1986年 | 12篇 |
1985年 | 8篇 |
1984年 | 8篇 |
1983年 | 8篇 |
1982年 | 11篇 |
1981年 | 8篇 |
1979年 | 9篇 |
1978年 | 8篇 |
1977年 | 6篇 |
1976年 | 8篇 |
1975年 | 8篇 |
1974年 | 7篇 |
1971年 | 6篇 |
排序方式: 共有3601条查询结果,搜索用时 15 毫秒
981.
A method of examining the separation of the boundary layer of air from a sports ball, specifically a football, is presented. Using a ball launcher, a non-spinning football is fired into a dust cloud. A high-speed camera records the ball passing through the dust cloud. Unlike wind-tunnel methods, the dust method described here allows for the examination of the boundary-layer separation without a ball-supporting arrangement. Boundary-layer separation for speeds surrounding the drag crisis is studied. Though the general trend is for the boundary layer to separate farther back on the ball as the ball’s centre-of-mass speed increases, anomalous behaviour is seen just past the drag crisis, namely a rise in the separation angle, followed by an expected decrease. 相似文献
982.
Knowledge Management Research & Practice - Information and knowledge have been cited over the last two decades as competitive advantage tools. Recently, the use of them has been discussed to... 相似文献
983.
The relationship between anagram solving and reading aloud proficiency was studied in Italian and French 6th grade children. Whereas a statistically significant relation was found in Italian, the link was not so direct in French. French children's ability in solving anagram problems seemed to benefit from their capacity in recognising written word-forms (lexical decision) and using the direct lexical reading route. Statistical properties concerning lexical entries appeared to be in an intermediate stage of computation. It is thus concluded that anagram solving may highlight some developmental stages and processing strategies in the acquisition and elaboration of written language. 相似文献
984.
Valérie Camos 《European Journal of Psychology of Education - EJPE》2003,18(3):251-265
The aim of this study was twofold. First, it evaluated the developmental changes on frequency of use, efficiency, and choice
of counting strategies from childhood to adulthood. Second, it determined the adaptation of the counting strategies to the
structural features of the task. Participants in seven age groups ranging from 5-year-old to adulthood were asked to count
dots in arrays varying on size, arrangement, density and size of the subgroups. The nature of the strategies used and their
efficiency, i.e. speed, accuracy and rate of manual pointing, were recorded using the overt behavior technique. The developmental
pattern of results for the four main strategies, counting by ones, by ns, addition and multiplication, was in line with Siegler’s
overlapping waves model. The structural features affected the use of the strategies since 13 years, except for the multiplication
strategy. Finally, intra- and inter-individual variability in strategy showed a monotonous increase with age. Implications
for understanding the development of counting skill are discussed. 相似文献
985.
986.
我国加入WT0将使企业的目标,竞争环境,面向的市场及管理重点等都发生转变,为此企业财务及管理软件也需作相应转变,企业财务及管理软件开发商和财经院校也都需做好调整和准备. 相似文献
987.
988.
The multistage 20 metre shuttle run test for aerobic fitness 总被引:18,自引:2,他引:16
A maximal multistage 20 m shuttle run test was designed to determine the maximal aerobic power of schoolchildren, healthy adults attending fitness class and athletes performing in sports with frequent stops and starts (e.g. basketball, fencing and so on). Subjects run back and forth on a 20 m course and must touch the 20 m line; at the same time a sound signal is emitted from a prerecorded tape. Frequency of the sound signals is increased 0.5 km h-1 each minute from a starting speed of 8.5 km h-1. When the subject can no longer follow the pace, the last stage number announced is used to predict maximal oxygen uptake (VO2max) (Y, ml kg-1 min-1) from the speed (X, km h-1) corresponding to that stage (speed = 8 + 0.5 stage no.) and age (A, year): Y = 31.025 + 3.238 X - 3.248A + 0.1536AX, r = 0.71 with 188 boys and girls aged 8-19 years. To obtain this regression, the test was performed individually. Right upon termination VO2 was measured with four 20 s samples and VO2max was estimated by retroextrapolating the O2 recovery curve at time zero of recovery. For adults, similar measurements indicated that the same equation could be used keeping age constant at 18 (r = 0.90, n = 77 men and women 18-50 years old). Test-retest reliability coefficients were 0.89 for children (139 boys and girls 6-16 years old) and 0.95 for adults (81 men and women, 20-45 years old).(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
989.
Renée Ribier 《Higher Education in Europe》1995,20(1-2):27-29
An aperçu of the French National Evaluation Committee is given. Its recent history, its functions, and its aims are evoked. The stages of an evaluation and the procedures for each stage are outlined. The aim is to help each institution and each targeted discipline to better understand itself and its future so as to fill its niche more fully and effectively. 相似文献
990.