全文获取类型
收费全文 | 59193篇 |
免费 | 2468篇 |
国内免费 | 22篇 |
出版年
2020年 | 715篇 |
2019年 | 844篇 |
2018年 | 1215篇 |
2017年 | 1225篇 |
2016年 | 1282篇 |
2015年 | 931篇 |
2014年 | 1110篇 |
2013年 | 5194篇 |
2012年 | 2074篇 |
2011年 | 2055篇 |
2010年 | 1272篇 |
2009年 | 1286篇 |
2008年 | 1819篇 |
2007年 | 1800篇 |
2006年 | 1622篇 |
2005年 | 1367篇 |
2004年 | 1387篇 |
2003年 | 1348篇 |
2002年 | 1299篇 |
2001年 | 1986篇 |
2000年 | 1848篇 |
1999年 | 1408篇 |
1998年 | 672篇 |
1997年 | 584篇 |
1996年 | 662篇 |
1995年 | 588篇 |
1994年 | 581篇 |
1993年 | 567篇 |
1992年 | 1158篇 |
1991年 | 1059篇 |
1990年 | 1046篇 |
1989年 | 987篇 |
1988年 | 965篇 |
1987年 | 892篇 |
1986年 | 894篇 |
1985年 | 942篇 |
1984年 | 786篇 |
1983年 | 659篇 |
1982年 | 518篇 |
1979年 | 795篇 |
1978年 | 585篇 |
1976年 | 502篇 |
1975年 | 617篇 |
1974年 | 703篇 |
1973年 | 715篇 |
1972年 | 613篇 |
1971年 | 562篇 |
1968年 | 612篇 |
1967年 | 535篇 |
1966年 | 511篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
21.
Leigh M. Riby Timothy J. Perfect Brian T. Stollery 《The Quarterly Journal of Experimental Psychology Section A: Human Experimental Psychology》2004,57(2):241-267
Previous research demonstrates that older adults are poor at dual tasking, but there is less agreement on whether their decrement is worse than that predicted from single-task performance. This study investigated whether task domain moderates dual-task costs in old age. In two experiments, young and older adults retrieved either previously learned associates (episodic retrieval) or overlearned category members (semantic retrieval) under single or working-memory load conditions, using cued recall (Experiment 1) and recognition (Experiment 2) procedures. In both experiments the proportional costs of dual tasking were age invariant for semantic retrieval but were particularly marked for episodic retrieval, although the size of the age effect was reduced in recognition compared to cued recall. The data suggest that age effects in dual tasking may be domain specific. 相似文献
22.
23.
Susan D. Healy John R. Krebs 《The Quarterly Journal of Experimental Psychology Section B: Comparative and Physiological Psychology》1992,45(1):33-47
The ability of two species of tits to remember the location and/or features of an object was tested in a delayed-matching-to-sample procedure. Three values of retention interval between presentation of the sample stimulus and the choice--30 sec, 5 min, and 15 min--were used. Both species performed at above-chance level at all retention intervals, and there was no significant decline in accuracy with increasing interval. A pool of 100 stimulus objects was used, but the results of control trials indicated that the birds responded primarily to location rather than stimulus features of the object itseif. Although the food-storing marsh tit tended to perform at a higher level than the non-storing great tit, the only significant difference between the species was in the first 50 trials of the first treatment, when the birds were acquiring the task. The results are discussed in relation to the hypothesized special memory capacity of food-storing birds. 相似文献
24.
John M. Pearce Helen Kaye Louis Collins 《The Quarterly Journal of Experimental Psychology Section B: Comparative and Physiological Psychology》1985,37(4):379-396
Three experiments, each using a single group of pigeons, are reported. In Experiment 1 subjects were initially trained with two stimuli, one of which was always followed by food, the other being reinforced according to a 50% partial reinforcement schedule. Subsequently a serial procedure was adopted in which an additional stimulus, C, was consistently followed by the partially reinforced CS. A second additional stimulus, A, was followed on half of its occurrences by the continuously reinforced CS, its remaining presentations being followed by nothing. The rate of autoshaped keypecking was substantially greater during A than during C. In the remaining experiments subjects received first-order conditioning with a single stimulus that was either partially (Experiment 2) or continuously (Experiment 3) reinforced. The stimuli A and C were then again introduced for serial autoshaping. Stimulus A was occasionally paired with the CS and occasionally followed by nothing, whereas stimulus C was always followed by the CS. As in Experiment 1, the rate of responding during A was greater than during C. It is proposed that one influence on the rate of autoshaped keypecking during a CS is the accuracy with which the immediate consequences of that CS are predicted. 相似文献
25.
Convergent and divergent stereo mechanisms were compared in their ability to recover structure from motion. Contrary to a recent result reported by Richards and Lieberman, no difference in their performance was found; both mechanisms appeared equally capable of supporting the perception of good structure from motion. Possible reasons for the disparate results are discussed. 相似文献
26.
27.
28.
29.
30.