全文获取类型
收费全文 | 3369篇 |
免费 | 178篇 |
国内免费 | 1篇 |
专业分类
3548篇 |
出版年
2023年 | 35篇 |
2022年 | 33篇 |
2021年 | 52篇 |
2020年 | 78篇 |
2019年 | 101篇 |
2018年 | 123篇 |
2017年 | 134篇 |
2016年 | 185篇 |
2015年 | 82篇 |
2014年 | 89篇 |
2013年 | 364篇 |
2012年 | 182篇 |
2011年 | 214篇 |
2010年 | 123篇 |
2009年 | 116篇 |
2008年 | 165篇 |
2007年 | 152篇 |
2006年 | 144篇 |
2005年 | 110篇 |
2004年 | 118篇 |
2003年 | 116篇 |
2002年 | 102篇 |
2001年 | 50篇 |
2000年 | 42篇 |
1999年 | 39篇 |
1998年 | 34篇 |
1997年 | 30篇 |
1996年 | 39篇 |
1995年 | 39篇 |
1994年 | 37篇 |
1993年 | 19篇 |
1992年 | 23篇 |
1991年 | 24篇 |
1990年 | 16篇 |
1989年 | 14篇 |
1988年 | 18篇 |
1987年 | 16篇 |
1986年 | 12篇 |
1985年 | 26篇 |
1984年 | 21篇 |
1983年 | 18篇 |
1982年 | 26篇 |
1981年 | 18篇 |
1980年 | 16篇 |
1979年 | 19篇 |
1977年 | 18篇 |
1976年 | 14篇 |
1975年 | 15篇 |
1974年 | 13篇 |
1973年 | 12篇 |
排序方式: 共有3548条查询结果,搜索用时 15 毫秒
941.
Intracerebral muscimol injection is widely used to inactivate discrete brain structures during behavioral tasks. However, little effort has been made to quantify the extent of muscimol diffusion. The authors report here electrophysiological and autoradiographic results obtained after muscimol injection (1 microg/microl) either into the nucleus basalis magnocellularis (0.1-0.4 microl) or into the thalamic reticular nucleus (RE, 0.05-0.1 microl). In 52 rats, multiunit recordings were collected either in the RE or in the auditory thalamus during the 2 h following muscimol injection. Decreases in neuronal activity were observed up to 3 mm from the injection site; their time of occurrence was a function of the distance between the injection and recording sites. Because these decreases cannot be explained by physiological effects, they likely reflected muscimol diffusion up to the recording sites. Autoradiographic studies involved 25 rats and different experimental conditions. Optical density (OD) measures indicated that after a survival time of 15 min, a 0.05 microl injection produced a labeled area of 5.25 mm(2) at the injection site and a rostrocaudal labeling of 1.7 mm. Increasing the survival time to 60 min, or increasing the injected volume to 0.1 microl, systematically led to a larger labeled area at the injection site (8-12 mm(2)) and to a larger rostrocaudal diffusion (2.0-2.5 mm). Direct quantifications of radioactivity by a high-resolution radioimager validated the OD measures and even indicated a larger muscimol diffusion (up to 3.25 mm). Thus, these data point out that muscimol diffusion after intracerebral microinjection is larger than usually supposed. The relationships between these results and those obtained in behavioral studies are discussed. 相似文献
942.
Cairo Valcarcel E Ijalba E Obler LK Gomez Lozano R Marin Llanes R Devia Collazos C Bouza Herrera C 《Brain and cognition》2002,48(2-3):291-296
Hemi-field visual-spatial attention was studied on a timed letter cancellation task in proficient readers from 7th to 9th grades. Participants maintained greater accuracy in identifying targets in the left quadrants (top/bottom) when compared with the right quadrants (top/bottom), revealing a leftward bias in their responses. Effects of gender and age were evident on performance; females scored significantly higher than males, and 9th graders scored significantly higher than 7th and 8th graders. Thus, a substantial shift in brain maturation may take place from 8th to 9th grades or from the ages of 13.0 to 14.11. Discriminative characteristics of the task are analyzed by assigning greater value to targets located in the top left quadrant. The 9th graders, as compared to the younger students, and the girls, as compared to the boys, evidenced a reading-direction-related bias toward systematic preference for the upper-left to lower-right quadrants. 相似文献
943.
Golinkoff RM Chung HL Hirsh-Pasek K Liu J Bertenthal BI Brand R Maguire MJ Hennon E 《Developmental psychology》2002,38(4):604-614
In the first study using point-light displays (lights corresponding to the joints of the human body) to examine children's understanding of verbs, 3-year-olds were tested to see if they could perceive familiar actions that corresponded to motion verbs (e.g., walking). Experiment 1 showed that children could extend familiar motion verbs (e.g., walking and dancing) to videotaped point-light actions shown in the intermodal preferential looking paradigm. Children watched the action that matched the requested verb significantly more than they watched the action that did not match the verb. In Experiment 2, the findings of Experiment 1 were validated by having children spontaneously produce verbs for these actions. The use of point-light displays may illuminate the factors that contribute to verb learning. 相似文献
944.
Rats learn the spatial pattern in which hidden caches of food are located. Once the pattern is learned, finding one or more
baited locations provides (positive) information about the remaining baited locations. In the present experiment, we examined
whether negative information (the absence of food in a location) would also be used in locating the remaining baited locations.
Rats were tested in an apparatus containing a matrix of vertical poles, on top of which food could be hidden. At the beginning
of the trial, the location of the baited poles was unpredictable, but the poles were always arranged in a linear pattern.
The rats learned the pattern and used both positive and negative information in locating baited poles. 相似文献
945.
David Walshe Elizabeth Lewis Kathleen O'Sullivan Sun I Kim 《Cyberpsychology & behavior》2005,8(6):532-537
There is a small but growing body of research supporting the effectiveness of computer-generated environments in exposure therapy for driving phobia. However, research also suggests that difficulties can readily arise whereby patients do not immerse in simulated driving scenes. The simulated driving environments are not "real enough" to undertake exposure therapy. This sets a limitation to the use of virtual reality (VR) exposure therapy as a treatment modality for driving phobia. The aim of this study was to investigate if a clinically acceptable immersion/presence rate of >80% could be achieved for driving phobia subjects in computer generated environments by modifying external factors in the driving environment. Eleven patients referred from the Accident and Emergency Department of a general hospital or from their General Practitioner following a motor vehicle accident, who met DSM-IV criteria for Specific Phobia-driving were exposed to a computer-generated driving environment using computer driving games (London Racer/Midtown Madness). In an attempt to make the driving environments "real enough," external factors were modified by (a) projection of images onto a large screen, (b) viewing the scene through a windscreen, (c) using car seats for both driver and passenger, and (d) increasing vibration sense through use of more powerful subwoofers. Patients undertook a trial session involving driving through computer environments with graded risk of an accident. "Immersion/presence" was operationally defined as a subjective rating by the subject that the environment "feels real," together with an increase in subjective units of distress (SUD) ratings of >3 and/or an increase of heart rate of >15 beats per minute (BPM). Ten of 11 (91%) of the driving phobic subjects met the criteria for immersion/presence in the driving environment enabling progression to VR exposure therapy. These provisional findings suggest that the paradigm adopted in this study might be an effective and relatively inexpensive means of developing driving environments "real enough," to make VR exposure therapy a viable treatment modality for driving phobia following a motor vehicle accident (MVA). 相似文献
946.
A wealth of data demonstrating that monkeys and apes represent number have been interpreted as suggesting that sensitivity to number emerged early in primate evolution, if not before. Here we examine the numerical capacities of the mongoose lemur (Eulemur mongoz), a member of the prosimian suborder of primates that split from the common ancestor of monkeys, apes and humans approximately 47–54 million years ago. Subjects observed as an experimenter sequentially placed grapes into an opaque bucket. On half of the trials the experimenter placed a subset of the grapes into a false bottom such that they were inaccessible to the lemur. The critical question was whether lemurs would spend more time searching the bucket when food should have remained in the bucket, compared to when they had retrieved all of the food. We found that the amount of time lemurs spent searching was indicative of whether grapes should have remained in the bucket, and furthermore that lemur search time reliably differentiated numerosities that differed by a 1:2 ratio, but not those that differed by a 2:3 or 3:4 ratio. Finally, two control conditions determined that lemurs represented the number of food items, and neither the odor of the grapes, nor the amount of grape (e.g., area) in the bucket. These results suggest that mongoose lemurs have numerical representations that are modulated by Webers Law. 相似文献
947.
This study investigated family interaction patterns associated with adolescent depression. Twenty adolescent–mother dyads with clinically depressed adolescents participated in the study. Twenty dyads with externalizing youths and 20 nonclinic dyads were included as controls. Dimensions of autonomy and relatedness were rated during a videotaped mother–adolescent problem-solving task. Adolescent perceptions of parent attachment were also evaluated. Results indicated that depressed adolescents and their mothers did not differ in their behavior compared with nonclinic adolescents. Dyads with externalizing adolescents showed the highest impairment in autonomy and relatedness. Depressed adolescents perceived the quality of their relationships with their parents to be impaired relative to nonclinic dyads, as did externalizing adolescents. 相似文献
948.
Kevin Crowley Maureen A. Callanan Harriet R. Tenenbaum & Elizabeth Allen 《Psychological science》2001,12(3):258-261
Young children's everyday scientific thinking often occurs in the context of parent-child interactions. In a study of naturally occurring family conversation, parents were three times more likely to explain science to boys than to girls while using interactive science exhibits in a museum. This difference in explanation occurred despite the fact that parents were equally likely to talk to their male and female children about how to use the exhibits and about the evidence generated by the exhibits. The findings suggest that parents engaged in informal science activities with their children may be unintentionally contributing to a gender gap in children's scientific literacy well before children encounter formal science instruction in grade school. 相似文献
949.
Within psychology there is a longstanding debate concerning whether large, fundamental differences between races and genders exist. Much of this research involves comparisons that are invidious (offensively discriminating) and supports a political ideology in which members of different groups are held to be fundamentally different, alien, and therefore destined to different spheres. In this paper, specific factors are identified that make research on group differences more likely to produce distorted and partial findings. In addition, studies are cited whose methodological strategies offer insight into the processes that create and maintain group differences. Such research may illuminate not only the differences between groups, but also the very meaning of group categories. The process of scholarly peer review should become sensitive to the features that make comparisons invidious, so as to incorporate them into the criteria used to evaluate research. 相似文献
950.
This study investigates the use of communication technology (CT) by therapists in private practice. CT has exploded in the last decade and therapists have begun to implement this technology in their work. It is important to understand better the types of technology therapists are using and how they decide which devices are most useful for clinical practice. Additionally, the availability of the therapist has long been debated and CT provides media to make therapists readily available. Results show that therapists have boundary concerns and ethical dilemmas regarding CT and often feel unprepared to handle inappropriate out-of-session contacts when they occur. 相似文献