全文获取类型
| 收费全文 | 2923篇 |
| 免费 | 45篇 |
| 国内免费 | 2篇 |
专业分类
| 教育 | 2195篇 |
| 科学研究 | 152篇 |
| 各国文化 | 23篇 |
| 体育 | 402篇 |
| 文化理论 | 62篇 |
| 信息传播 | 136篇 |
出版年
| 2023年 | 30篇 |
| 2022年 | 47篇 |
| 2021年 | 65篇 |
| 2020年 | 113篇 |
| 2019年 | 175篇 |
| 2018年 | 224篇 |
| 2017年 | 226篇 |
| 2016年 | 163篇 |
| 2015年 | 109篇 |
| 2014年 | 103篇 |
| 2013年 | 632篇 |
| 2012年 | 121篇 |
| 2011年 | 79篇 |
| 2010年 | 74篇 |
| 2009年 | 77篇 |
| 2008年 | 65篇 |
| 2007年 | 56篇 |
| 2006年 | 60篇 |
| 2005年 | 42篇 |
| 2004年 | 33篇 |
| 2003年 | 41篇 |
| 2002年 | 30篇 |
| 2001年 | 25篇 |
| 2000年 | 24篇 |
| 1999年 | 22篇 |
| 1998年 | 23篇 |
| 1997年 | 16篇 |
| 1996年 | 25篇 |
| 1995年 | 20篇 |
| 1994年 | 22篇 |
| 1993年 | 17篇 |
| 1992年 | 9篇 |
| 1991年 | 15篇 |
| 1990年 | 14篇 |
| 1989年 | 18篇 |
| 1988年 | 18篇 |
| 1987年 | 13篇 |
| 1986年 | 6篇 |
| 1985年 | 7篇 |
| 1984年 | 8篇 |
| 1983年 | 7篇 |
| 1982年 | 9篇 |
| 1981年 | 6篇 |
| 1980年 | 5篇 |
| 1979年 | 7篇 |
| 1978年 | 6篇 |
| 1977年 | 5篇 |
| 1976年 | 7篇 |
| 1975年 | 8篇 |
| 1974年 | 6篇 |
排序方式： 共有2970条查询结果，搜索用时 609 毫秒
91.
92.
93.
The aim of this study was to assess the effect of stress on a previously acquired motor coordination. Following a longitudinal learning experiment, four participants performed oscillations on a ski simulator, either in normal or stressful conditions. The results showed that the amplitude of the oscillations decreased under stress, but no significant effect was seen regarding coordination, suggesting the strong resistance to stress of overlearned behaviour. Nevertheless, for one participant, a transient regression towards a former stage of learning was observed. This result was consistent with the regression hypothesis formulated by Fuchs (1962). 相似文献
94.
95.
The aim of this study was to determine the physiological responses to orienteering by examining the interrelationships between the information provided by a differential global positioning system (dGPS) about an orienteer's route, speed and orienteering mistakes, portable metabolic gas analyser data during orienteering and data from incremental treadmill tests. Ten male orienteers completed a treadmill threshold test and a field test; the latter was performed on a 4.3 km course on mixed terrain with nine checkpoints. The anaerobic threshold, threshold of decompensated metabolic acidosis, respiratory exchange ratio, onset of blood lactate accumulation and peak oxygen uptake (VO2peak) were determined from the treadmill test. Time to complete the course, total distance covered, mean speed, distance and timing of orienteering mistakes, mean oxygen uptake, mean relative heart rate, mean respiratory exchange ratio and mean running economy were computed from the dGPS data and metabolic gas analyser data. Correlation analyses showed a relationship between a high anaerobic threshold and few orienteering mistakes (r = - 0.64, P < 0.05). A high threshold of decompensated metabolic acidosis and VO2peak were related to a fast overall time (r = -0.70 to -0.72, P < 0.05) and high running speed (r = 0.64 to 0.79, P < 0.05 and P < 0.01, respectively), and were thus the best predictors of performance. 相似文献
96.
97.
98.
99.
Gérald Séguin 《Journal of The Franklin Institute》1980,309(3):179-189
A sequence of metrics {DN} is said to be additive and matched to a discrete memoryless channel (DMC) if DN is the sum on its coordinates of N single letter metrics and if the maximum likelihood decoder for sequences of length N is a minimum DN-distance decoder. Necessary and sufficient conditions on the transition probabilities of a DMC for the existence of a sequence of additive metrics matched to it are given. In the case of the binary channel these are shown to be equivalent to the channel being symmetric. Explicit transition probabilities are given for a large class of ternary DMCs with an associated sequence of additive matched metrics. The problem solved here may be considered a generalization of the problem of finding the DMCs matched to the Lee metric solved by Chiang and Wolf in 1971 (2). 相似文献
100.