全文获取类型
收费全文 | 2412篇 |
免费 | 109篇 |
出版年
2021年 | 20篇 |
2020年 | 40篇 |
2019年 | 40篇 |
2018年 | 61篇 |
2017年 | 62篇 |
2016年 | 58篇 |
2015年 | 53篇 |
2014年 | 54篇 |
2013年 | 248篇 |
2012年 | 91篇 |
2011年 | 99篇 |
2010年 | 54篇 |
2009年 | 66篇 |
2008年 | 110篇 |
2007年 | 90篇 |
2006年 | 96篇 |
2005年 | 74篇 |
2004年 | 77篇 |
2003年 | 55篇 |
2002年 | 72篇 |
2001年 | 42篇 |
2000年 | 57篇 |
1999年 | 55篇 |
1998年 | 34篇 |
1997年 | 31篇 |
1996年 | 28篇 |
1994年 | 19篇 |
1993年 | 23篇 |
1992年 | 41篇 |
1991年 | 28篇 |
1990年 | 36篇 |
1989年 | 25篇 |
1988年 | 36篇 |
1987年 | 35篇 |
1986年 | 17篇 |
1985年 | 30篇 |
1984年 | 22篇 |
1983年 | 21篇 |
1980年 | 17篇 |
1979年 | 35篇 |
1977年 | 17篇 |
1976年 | 30篇 |
1975年 | 22篇 |
1974年 | 20篇 |
1973年 | 20篇 |
1972年 | 21篇 |
1971年 | 23篇 |
1968年 | 27篇 |
1967年 | 18篇 |
1966年 | 19篇 |
排序方式: 共有2521条查询结果,搜索用时 15 毫秒
11.
Rats were allowed to forage in a simulated natural environment made up of eight food sources (patches) each containing a fixed number of pellets. Two of the eight contained an extra supply of peanuts. The peanut patches were signaled by an olfactory/visual cue located at the bottom of the ladder leading to the patch. In successive phases the number of sessions per day, height of the patches, and availability of peanuts were manipulated. Subjects showed evidence of discrimination learning under these conditions, although the degree of discriminatory behavior varied as a function of environmental manipulations. Assessment of behavior within foraging sessions showed that subjects systematically changed their patterns of utilization of patches across time. Sampling or exploration, as well as food reinforcement, seem implicated in these results. 相似文献
12.
13.
For 3 consecutive days cockroaches (Periplaneta americana) were exposed to either escapable, inescapable, or no shock in an escape task. Twenty-four hours later they were tested in a shuttlebox escape task. There were reliable differences between escapable and inescapable animals and between inescapable and control animals in both escape latencies and the number of failures to escape. 相似文献
14.
Perceptual organization of acoustic stimuli by budgerigars (Melopsittacus undulatus): III. Contact calls 总被引:1,自引:0,他引:1
S D Brown R J Dooling K O'Grady 《Journal of comparative psychology (Washington, D.C. : 1983)》1988,102(3):236-247
We trained budgerigars by operant conditioning to discriminate among a set of contact calls in a same-different task and analyzed response latencies from this task by using multidimensional-scaling (MDS) and cluster-analysis procedures. Humans listened to the same calls and indicated the similarity between pairs of calls by a direct rating procedure. An MDS program (sindscal) was used to arrange these complex acoustic stimuli in multidimensional space reflecting perceptual organization. Multiple regression techniques were used to identify the acoustic characteristics of contact calls that were correlated with the perceptual dimensions obtained from MDS. A number of spectral characteristics (e.g., peak frequency, rate of frequency modulation, and concentration of spectral energy) emerged as important for both budgerigars and humans, but the relative salience of these cues differed for the two species. Additional tests with two groups of budgerigars--cagemates and noncagemates--showed that experience with calls can change the salience of various acoustic characteristics used for perceptual organization and individual recognition. 相似文献
15.
Fifteen rats performed in a standard radial-arm maze task (Experiment 1) and in a modified task with a set of forced choices and a 15-min retention interval prior to completion of the maze (Experiment 2). In addition to the standard measure of choice in the radial-arm maze, orientation toward arms was measured and considered to constitute go-no-go "microchoice" decisions. Rats investigated but rejected many arms. A model of choice was developed in which it was assumed that choice decisions about arms were made independently and that microchoices were not selectively guided toward baited arms. The model performed nearly as well as the rats. These results place important limitations on the theory that choice behavior in the radial-arm maze is guided by a cognitive map. 相似文献
16.
Gareth Crossley 《British Journal of Guidance & Counselling》1992,20(3):291-302
A small self-help manual composed of seven exercises for married couples was produced. Married couples from a Christian community were invited to participate in the use of the manual and to work through the exercises for at least two hours per week. Seven of the couples agreed to be interviewed at the close of the project and to share their experiences, insights and observations. Five of the seven couples reported finding the manual distinctly helpful. One couple found no benefit from the exercises but were sufficiently interested to complete the project. The remaining couple regarded the exercises as largely unhelpful and expressed reservations about their use. The results of this exploratory research suggest that the use of a self-help manual such as the one produced here is beneficial to some married couples. There are, however, limitations. These limitations are explored and discussed, and suggestions for further research are presented. 相似文献
17.
This study sought to investigate the effects of mild head injury on a particular type of cognitive ability, verbal analogical
reasoning. The performance of 19 individuals with head injuries was compared to a group of 30 control subjects matched for
age, education, and gender on 100 verbal analogies. Solution times and error rates were modeled. Unstandardized regression
weights for individual subjects were correlated with subjects’ performance on a number of standardized ability tests. Results
showed that compared to the control subjects, the head injured subjects: (a) were significantly slower to solve the analogies,
and were particularly slow to perform certain processes: encoding/inference and comparison; (b) tended to show greater variability
in performance; and (c) had data that had a poorer componential model fit. The data suggest that analogical reasoning is affected
by a head injury, and that certain information processes may be responsible for performance deficits. 相似文献
18.
19.
20.