首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   38864篇
  免费   1527篇
  国内免费   15篇
  2020年   468篇
  2019年   605篇
  2018年   814篇
  2017年   865篇
  2016年   872篇
  2015年   599篇
  2014年   744篇
  2013年   3113篇
  2012年   1355篇
  2011年   1368篇
  2010年   888篇
  2009年   803篇
  2008年   1206篇
  2007年   1197篇
  2006年   1078篇
  2005年   930篇
  2004年   866篇
  2003年   824篇
  2002年   832篇
  2001年   1166篇
  2000年   1127篇
  1999年   875篇
  1998年   386篇
  1997年   375篇
  1995年   353篇
  1994年   346篇
  1993年   349篇
  1992年   738篇
  1991年   641篇
  1990年   698篇
  1989年   607篇
  1988年   636篇
  1987年   598篇
  1986年   603篇
  1985年   544篇
  1984年   500篇
  1983年   479篇
  1982年   347篇
  1979年   568篇
  1978年   397篇
  1975年   450篇
  1974年   496篇
  1973年   534篇
  1972年   396篇
  1971年   394篇
  1970年   351篇
  1969年   403篇
  1968年   480篇
  1967年   428篇
  1966年   357篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
291.
I examined preweanling rats' (Rattus norvegicus) expression of ultrasounds and secretion of ACTH when exposed to unfamiliar adult male rats or to their mothers. Pups at 7 days of age produced similar levels of ultrasonic vocalization near both unfamiliar males and mothers. However, these pups could discriminate familiar from unfamiliar adults because ACTH was significantly higher in pups near adult males than in those near mothers. At 14 days of age, pups avoided adult males but not their mothers; therefore, adult males represented a significant threat. Importantly, 14-day-old rats significantly reduced ultrasound production only when near adult males. Pups at 21 days of age no longer emitted ultrasounds when socially isolated or when near conspecific adults. In addition, 14- and 21-day-old rats produced similar elevated ACTH levels across stimulus conditions. Results show significant changes in preweanling rats' responses to conspecific adults.  相似文献   
292.
Measures of spatial cognition, neighborhood knowledge, and neighborhood use from the research described by Walsh, Krauss, and Regnier (1981) were examined to determine if laboratory tests of spatial cognition were significant predictors of older adults' use of their neighborhoods. The overall results show that laboratory-based measures of spatial cognition and subjects' knowledge of their neighborhoods are both significant predictors of their use of neighborhood goods and services. The ability to learn and remember the location and orientation of objects, when contextual cues were not provided at test, was more predictive of the participants' neighborhood use than either the participants' number of years in the neighborhood or their mobility. Spatial memory as measured by the Educational Testing Service Building Memory task predicted neighborhood knowledge, which was predictive of neighborhood use.  相似文献   
293.
Elders exposed to either progressive or imaginal relaxation procedures reported significant relaxation effects and showed improvement on measures of personal functioning. The results of the Physical Assessment Scale of the Relaxation Inventory indicated that relaxation responses were acquired within and across sessions. Large, consistent changes in relaxation occurred in all 4 sessions. The Symptom Checklist-90-R, which measures self-reported personal adjustment, showed significant positive changes following relaxation training and at 1-month follow-up. Elders who imagined muscle tension release profited as much as those engaged in actual muscle tension-release activities. This finding is of importance for older adults who may experience physical limitations that contraindicate muscle-tension-release procedures.  相似文献   
294.
Aging and shifts of visual spatial attention.   总被引:2,自引:0,他引:2  
Three experiments examined adult age differences in the efficiency of endogenous (voluntary) and exogenous (involuntary) attention shifts. Younger and older subjects performed a spatial cuing task in which abruptly onset peripheral cues (Experiment 1) or central, symbolic cues (Experiments 2 and 3) were presented before a target stimulus at intervals ranging from 50 to 250 ms. With peripheral cues, the magnitude of cuing effects was at least as great for older as for younger adults and followed a similar time course. Similar results were obtained with symbolic cues, although cuing effects for older adults varied with cue difficulty. The results suggest that cue encoding may decline with advancing age but that the efficiency of the shift process is preserved.  相似文献   
295.
Eighty younger (less than 50 years, M = 28 years) and 80 older (more than 50 years, M = 69 years) Type A and Type B Ss were evaluated for Type A behavior pattern using the Structured Interview (SI) and given personality tests for anxiety, depression, anger, aggression, hostility, and anger-in-anger-out. Ss also underwent an emotion induction procedure. Videotapes of the emotion induction procedure (N = 160) and the SI (N = 80) were coded for facial expression of emotion. Type As did not differ from Bs on anxiety or depression but did on anger and aggression. Type As showed anger inhibition and anger bound to shame, as predicted by emotion socialization theory. The greatest number of differential effects were observed between age groups. Older individuals, in general, were more emotionally expressive than younger Ss across a range of emotions. Women appeared more conflicted about anger expression than men, and Type A women more so than Type A men.  相似文献   
296.
The authors used a correlated motion paradigm to investigate the effects of aging and gender on motion sensitivity. In 2 experiments with a total of 50 elderly and 50 young subjects, motion thresholds were significantly higher for elderly women. The correlated motion signal, which was embedded in random motion, may have been coherent to subjects in much the same way a form is in Witkin's Embedded Figures Test (EFT). In Experiment 2, EFT scores were obtained. A significant positive relationship between motion thresholds and EFT performance was found within each age group. Although gender-related perceptual style differences may contribute to motion perception effects, the authors argue that a common neural factor contributes to performance on both the EFT and the correlated motion task.  相似文献   
297.
The present paper compares behavior-analytic and cognitive treatments of the concept of psychological history with regard to its role in current action. Both treatments take the position that the past bears some responsibility for the present, and are thereby obligated to find a means of actualizing the past in the present. Both do so by arguing that the past is brought to bear in the present via the organism. Although the arguments of the two positions differ on this issue, neither provides a complete account. An unconventional treatment of psychological history is proposed, the logic of which is exemplified in anthropological, biological, and psychological perspectives. The unconventional treatment in psychological perspective holds that (a) the organism's interaction with its environment, not the organism itself, changes with experience; and (b) the past interactions of an organism exist as, and only as, the present interactions of that organism. This solution to the problem of psychological history provides obligations and opportunities for analysis that are not available when the more conventional positions of cognitivism and behavior analysis are adopted.  相似文献   
298.
Hispanic Americans have one of the highest rates of HIV seroprevalence among all ethnics groups in the US, with high rates being especially noticeable among women and children. Were it known which cultural factors have the most influence on whether Hispanics engage in high-risk behavior for HIV transmission, prevention interventions could be targeted accordingly. To that end, this study was mounted to identify which Hispanic cultural factors relate to condom use. 117 males and 73 females aged 17-56 years of mean age 25.67 were surveyed in Washoe county, Nevada. These mostly young adults had recently immigrated to the western US. It was initially posited that fate orientation, male- female relationships, family relationships, machismo behavior, and religion would have equal influence with respect to condom use. Analysis found that condom use was largely associated with and determined by men who are the principal buyers of condoms. A machismo attitude toward protecting women by using condoms was also associated with condom use. Neither fate orientation with respect to AIDS, nor religion were important determinants of condom use, even though 86.5% of the respondents were Catholic. The degree to which respondents adhered to traditional Hispanic cultural values was influenced by the degree of education and acculturation. On the basis of these findings, the authors suggest targeting AIDS prevention messages to males, while emphasizing the protection of women through condom use. They also suggest that both education and acculturation levels be assessed before implementing prevention programs.  相似文献   
299.
The importance of educating students about stress and stress management is emphasized, because students will confront stressors throughout their life span. In this article the author summarizes major stress theories and shows how stress theory and stress management strategies can be integrated into existing school curricula.  相似文献   
300.
The Treatment Evaluation Inventory (TEI), a frequently used measure of treatment acceptability, was used by 164 undergraduates to rate the acceptability of each of the following treatments: differential reinforcement of other behavior, exclusionary time-out, overcorrection, medical restraint, contingent electric shock, and physical restraint. TEI ratings of each treatment type were grouped separately, variance-covariance matrices were formed and compared, and data were subjected to factor analysis. The results indicated that the factor structure of the TEI varied with the treatment it was used to evaluate. Item analysis of the TEI indicated a high degree of internal consistency, although item-total correlations varied between rated treatments. The findings suggest that although the TEI is a reliable instrument, sensitive assessment of the treatment acceptability construct probably requires multidimensional measurement.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号