全文获取类型
收费全文 | 3604篇 |
免费 | 106篇 |
国内免费 | 2篇 |
专业分类
3712篇 |
出版年
2020年 | 35篇 |
2019年 | 37篇 |
2018年 | 60篇 |
2017年 | 65篇 |
2016年 | 78篇 |
2015年 | 48篇 |
2014年 | 62篇 |
2013年 | 458篇 |
2012年 | 100篇 |
2011年 | 108篇 |
2010年 | 63篇 |
2009年 | 81篇 |
2008年 | 94篇 |
2007年 | 99篇 |
2006年 | 126篇 |
2005年 | 129篇 |
2004年 | 91篇 |
2003年 | 101篇 |
2002年 | 92篇 |
2001年 | 54篇 |
2000年 | 48篇 |
1999年 | 71篇 |
1998年 | 78篇 |
1997年 | 53篇 |
1996年 | 53篇 |
1995年 | 49篇 |
1994年 | 47篇 |
1993年 | 52篇 |
1992年 | 41篇 |
1991年 | 58篇 |
1990年 | 43篇 |
1989年 | 58篇 |
1988年 | 40篇 |
1987年 | 37篇 |
1986年 | 40篇 |
1985年 | 36篇 |
1984年 | 59篇 |
1983年 | 44篇 |
1982年 | 61篇 |
1981年 | 49篇 |
1980年 | 45篇 |
1979年 | 52篇 |
1978年 | 53篇 |
1977年 | 41篇 |
1976年 | 47篇 |
1975年 | 40篇 |
1974年 | 51篇 |
1973年 | 39篇 |
1969年 | 35篇 |
1968年 | 33篇 |
排序方式: 共有3712条查询结果,搜索用时 15 毫秒
981.
In this study, we investigated where people look on talkers' faces as they try to understand what is being said. Sixteen young adults with normal hearing and demonstrated average speechreading proficiency were evaluated under two modality presentation conditions: vision only versus vision plus low-intensity sound. They were scored for the number of words correctly identified from 80 unconnected sentences spoken by two talkers. The results showed two competing tendencies: an eye primacy effect that draws the gaze to the talkers eyes during silence and an information source attraction effect that draws the gaze to the talker's mouth during speech periods. Dynamic shifts occur between eyes and mouth prior to speech onset and following the offset of speech, and saccades tend to be suppressed during speech periods. The degree to which the gaze is drawn to the mouth during speech and the degree to which saccadic activity is suppressed depend on the difficulty of the speech identification task. Under the most difficult modality presentation condition, vison only, accuracy was related to average sentence difficulty and individual proficiency in visual speech perception, but not to the proportion of gaze time directed toward the talkers mouth or toward other parts of the talker's face. 相似文献
982.
Monbiot G 《Science and engineering ethics》2003,9(1):49-57
The belief that science is "a driver of growth in the knowledge economy" has led in recent decades to increasing encouragement by government of the involvement of industry and of commerce in the sponsorship and direction of research in universities, and to the increasing influence of industrial representatives on advisory panels associated with the publicly funded scientific research councils. By extending the doctrine of commercial confidentiality into university laboratories, inconvenient findings have been suppressed, and both free endeavour and free speech undermined. This has narrowed our scientific horizons and compromised government advisors. It is argued that scientific freedom is a guarantor of our wider liberties. Science, which tells us who we are and how we can live better, is being distorted so twisting our understanding of the ways in which we might progress, shutting off alternatives to existing models of development. Business now stands as a guard dog at the gates of perception. Only the inquiries which suit its needs are allowed to pass. 相似文献
983.
Wagstaff GF MacVeigh J Boston R Scott L Brunas-Wagstaff J Cole J 《The Journal of psychology》2003,137(1):17-28
984.
Seven trends regarding the categories that tend to be impaired/preserved in category-specific semantic deficits were identified. The authors hypothesized that these trends arise despite the multiple sources of variation in patient testing because numerous factors that structure semantic memory probabilistically converge to make some categories of knowledge more susceptible to damage than others. Analysis of semantic feature norms and corpus data for 541 concepts revealed that differences in the distribution of knowledge types across categories are sufficient to explain 6 of the trends and are necessary to explain loss of knowledge about nonliving things. Feature informativeness, concept confusability, visual complexity, familiarity, and name frequency contributed to this patterning and provide insight into why knowledge about living things is most often impaired. 相似文献
985.
In the first stage of Experiments 1-3, subjects learned to associate different geometrical figures with colors or with verbal labels. Performance in Stage 2, in which the figures signaled which of 2 motor responses should be performed, was superior in subjects required to make the same response to figures that had shared the same Stage 1 associate. A third stage of testing showed that the events used as associates in Stage 1 were capable of evoking the motor response trained in Stage 2, an outcome predicted by an associative interpretation of such transfer effects. Experiment 4 provided evidence that the relevant associations can be effective in controlling motor responding even when subjects report an antagonistic relationship between events. 相似文献
986.
Harold G. Koenig Linda K. George Patricia Titus Keith G. Meador 《Journal of religion and health》2003,42(4):301-314
Background: Religious and spiritual beliefs and practices are common among medical inpatients, and may impact length of hospital stay (LOS) and other health services (HSU) during hospitalization. Methods: 812 consecutively admitted patients age 50 or over to Duke University Medical Center were assessed. Measures of religiousness and spirituality included religious TV/radio (RTV), self-rated religiousness (SRR), observer-rated spirituality (ORS), and daily spiritual experiences (DSE). The primary outcome was LOS. Results: RTV and SRR predicted longer LOS, whereas ORS and DSE predicted shorter LOS (p 0.05). Effects of RTV onLOS were stronger among women, but explained by worse health status. The effects of DSE on LOS were stronger among non-whites. Among those reporting high DSE, diagnostic tests and total procedures also tended to be less common. Conclusions: Religious activities, attitudes, and spiritual experiences are weak predictors of LOS and HSU during hospitalization. Whether the prediction is positive or negative depends on the religious or spiritual characteristic. 相似文献
987.
The emotional effect of personal involvement in physical aggression was examined in a random sample of 1,753 adults from Ontario, Canada, using Computer Assisted Telephone Interviewing (response rate of 67%). Respondents reported a range of emotional responses from feeling good or justified to feeling angry, upset, terrified, disgusted, hurt, and embarrassed. Open-ended responses regarding emotional response were rated by the authors for 149 incidents of aggression, which yielded five categories: (1) positive impact 4%, (2) no feeling or no effect 31%, (3) mildly negative 20%, (4) moderately negative 28%, and (5) severely negative 17% (Kappa statistic of interrater agreement=.77). The substantial proportion of incidents involving positive or no emotional response suggests that a greater understanding of aggression among individuals can be gained by the development and application of a quantitative measure of emotional response that reflects the full range of emotions (positive and negative), using dimensions identified in this study such as feeling upset, fear, and anger. 相似文献
988.
This study examined predictors and outcomes of attendance in two standard components of a multifaceted preventive intervention aimed at children with early-onset disruptive behavior after 3 years of intervention. Mean rate of attendance in the Family Program, but not the Summer School Program, differed by level of child disruptiveness (grouping variable). Although predictors of attendance (SES, single-parent status, child IQ) did not differ across high- and low-disruptive groups, predictors of outcome were moderated by level of child disruptiveness for academic achievement and aggression outcomes, but not for social competence. Higher attendance in the Summer Program was associated with higher child social competence at Year 3 for all children. For academic achievement, higher attendance in the Summer Program was associated with higher scores for mild/moderately disruptive children and lower scores for highly disruptive children in Year 3. Higher attendance in the Family Program was associated with lower aggression scores for mild/moderately disruptive children. Findings highlight the importance of matching intervention components to the assessed or expressed needs of client subgroups. 相似文献
989.
990.
Rats were exposed to a radial maze containing six black smooth arms and six wire-grid-covered arms and a striped 'exit arm'
in experiment 1. The probability of a black or grid arm being baited (5/6 vs 1/6) with sunflower seeds was associated with
its proximal cue for some rats (the Relevant Arm Cue group) but not for others (the Irrelevant Arm Cue group). All rats could
terminate a trial and receive a highly preferred morsel of apple by entering the exit arm only after having sampled all six
seed-baited arms. Relevant Arm Cue rats usually chose some arms from the more densely baited set before choosing an arm from
the less densely baited set and made fewer reentries than Irrelevant Arm Cue rats. Although such clustered, higher choice
accuracy in the Relevant Arm Cue group corresponds to human clustered, better recall of verbal items from lists hierarchically
organized by categories, these rats did not similarly exhaustively retrieve items (arm locations). That is, when required
to terminate a trial by entering the 'exit' arm for an apple morsel after having sampled all seed-baited arms, both groups
were equally unable to withhold making nonrewarded premature exits. This nonexhaustive foraging search pattern was maintained
in the next two experiments in which the radial maze was reduced to three black and three grid arms along with the striped
'exit' arm and in which black and grid arm cues were paired with number of seeds (eight or one) in an arm for Relevant Arm
Cue rats. Although Relevant Arm Cue rats displayed perfect clustering by entering all eight-seeded arms before a one-seeded
arm, they made more premature exits and reentries into eight-seeded arms in experiment 2 or when forced to enter all eight-seeded
arms in experiment 3 than did Irrelevant Arm Cue rats. These foraging tendencies prevent accurate estimations of the amount
of information (i.e., arm locations) rats can 'chunk'.
Electronic Publication 相似文献