全文获取类型
收费全文 | 11995篇 |
免费 | 320篇 |
国内免费 | 3篇 |
专业分类
12318篇 |
出版年
2021年 | 92篇 |
2020年 | 136篇 |
2019年 | 120篇 |
2018年 | 301篇 |
2017年 | 269篇 |
2016年 | 397篇 |
2015年 | 255篇 |
2014年 | 223篇 |
2013年 | 790篇 |
2012年 | 588篇 |
2011年 | 599篇 |
2010年 | 242篇 |
2009年 | 234篇 |
2008年 | 343篇 |
2007年 | 353篇 |
2006年 | 303篇 |
2005年 | 1557篇 |
2004年 | 899篇 |
2003年 | 695篇 |
2002年 | 391篇 |
2001年 | 166篇 |
2000年 | 118篇 |
1999年 | 152篇 |
1998年 | 116篇 |
1997年 | 113篇 |
1996年 | 97篇 |
1995年 | 90篇 |
1994年 | 89篇 |
1993年 | 86篇 |
1992年 | 120篇 |
1991年 | 132篇 |
1990年 | 132篇 |
1989年 | 98篇 |
1988年 | 86篇 |
1987年 | 104篇 |
1986年 | 106篇 |
1985年 | 106篇 |
1984年 | 95篇 |
1983年 | 94篇 |
1982年 | 68篇 |
1981年 | 81篇 |
1980年 | 71篇 |
1979年 | 108篇 |
1978年 | 84篇 |
1977年 | 81篇 |
1976年 | 79篇 |
1975年 | 87篇 |
1974年 | 104篇 |
1973年 | 82篇 |
1966年 | 62篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
161.
162.
T K?hler J Dunker O Zander 《Zeitschrift für experimentelle und angewandte Psychologie》1990,37(3):447-458
The number of active sweat glands (PSI), heart rate, systolic (SBP) and diastolic blood pressure (DBP) were assessed every 2 minutes in 109 male blood donors. Three measurements were taken at the beginning (adaptation phase), three later but before blood donation (baseline), one during the venous puncture (phase 3), three thereafter but still during donation (phase 4), and four after removal of the cannula (phase 5). Analysis of variance yielded significant differences between phases; PSI and SBP behaved similarly, decreasing from adaptation to baseline, rising during puncture, and decreasing again thereafter. Mean within-subject correlations between variables were significantly above 0. Between-subjects correlations were significantly negative for PSI and DBP. This is best explained by the influence of age on both variables. Correlations of PSI values as determined by three raters had a mean of 0.90. The study shows that the PSI is a very sensitive indicator of stress that is easily accessible also in field studies. 相似文献
163.
Thomas H. Ollendick Ross W. Greene Mark D. Weist Donald P. Oswald 《Journal of abnormal child psychology》1990,18(6):699-713
The purpose of this study was to examine the predictive validity of a teacher nomination procedure for identifying at- risk children. Two hundred and twenty-five children were nominated by their teachers as well- adjusted (n= 75), socially withdrawn (n=76), or socially aggressive (n=74) during the fourth grade. Five years later, 198 of these children (88%) were located and their adjustment evaluated. Significant differences among the nominated children were found on a variety of measures, including academic grades, sociometric status, and social behavior. In addition, differences in school dropout and delinquent offenses were noted. Results are discussed in terms of the validity of teacher nomination procedures and their utility in identifying at- risk youth. 相似文献
164.
A kinematic analysis of anticipatory coarticulation in the speech of anterior aphasic subjects using electromagnetic articulography 总被引:1,自引:1,他引:0
An investigation was made into the extent and time course of anticipatory coarticulation in the speech of two normal and two anterior aphasic, German-speaking subjects. Both labial and velar coarticulation gestures were investigated. Subjects produced sentences containing target words contrasting in postconsonantal vowel rounding (e.g., [geli:ge]/[gely:gel]) and in nasality (e.g., [ti:de]/[ti:ne]). Speech kinematics were monitored by means of electromagnetic articulography. The data revealed that for correct productions, aphasic speakers' coarticulatory patterns were more highly variable than those of control subjects. These differences, however, were found chiefly for spatial displacement characteristics, while the temporal aspects of articulator movement necessary for anticipatory coarticulation appeared largely intact. Articulator mistiming did not appear to explain a small corpus of stop/nasal substitution errors produced by one of the aphasic speakers. 相似文献
165.
Toward a Process Analysis of Emotions: The Case of Surprise 总被引:1,自引:0,他引:1
Based on an earlier model of the processes elicited by surprising events, the present studies provide evidence for one of these processes, the evaluation of the surprising event's relevance for ongoing activities (action-relevance check). The central prediction tested was that, if unexpected events elicit among other processes an action-relevance check, then response delay on a concurrent task will be more pronounced in a condition where this process is more elaborate and hence takes more time. In accord with this prediction, Experiment 1 found that an unexpected appearance change of the imperative stimulus in a choice reaction time (RT) task caused greater response delay than an equivalent appearance change of a distractor stimulus. Experiment 2 replicated this finding and tested several additional predictions that concerned the effects on response delay of a second appearance change of either the imperative or the distractor stimuli. These predictions, which were also mostly confirmed, were derived by combining the logic underlying the first study with the assumption that once made, appraisals of unexpected events are stored as part of the situational schema and are reused when the same or similar events reoccur leading to an abbreviation of appraisal processes. Experiment 3 once more replicated the basic finding of the previous studies and ruled out a possible alternative explanation. It is suggested that the proposed RT method of process verification may be of broader interest as a tool to study appraisal processes in emotion. 相似文献
166.
167.
When procedural artifacts are controlled, it has been difficult to demonstrate directed forgetting in pigeons. However, previous research with pigeons has not allowed for the reallocation of working memory (from forget items to remember items) on forget-cued trials as is possible in human directed forgetting experiments. In the present experiment, directed forgetting was found while controlling for procedural artifacts and allowing the pigeons to reallocate memory resources on forget trials. The results indicate that under these conditions, pigeons have active control over memory processing. 相似文献
168.
A multidisciplinary group of genetic and other professionals discuss a complex case of familial conflict over access to genetic information. One twin wishes to know the results of her deceased mother's tests for BRCA1 mutations; a second twin objects to researchers making this information available. As the case discussion unfolds, the apparent facts of this case are called into question and the lines of ethical certainty become less clear. 相似文献
169.
Silvia A. Bunge Juliane Mauelshagen Thomas J. Carew 《Neurobiology of learning and memory》1997,67(3):259-263
Tail shock induces reflex sensitization inAplysiaand, in parallel, induces a number of modulatory effects in central neurons, such as increased excitability in tail sensory neurons (SNs) and facilitation of synaptic transmission from SNs to motor neurons. Both of these modulatory effects are mimicked by exogenous application of serotonin (5HT) or electrical stimulation of the tail nerve P9. In the present study we examined the activation thresholds for increased excitability and synaptic facilitation induced by either 5HT or P9 stimulation. We found that the concentration of 5HT sufficient to produce a significant increase in excitability produced no significant synaptic facilitation and, conversely, that the intensity of nerve stimulation sufficient to produce significant synaptic facilitation produced no excitability changes. This reversal of relative thresholds for these modulatory effects may reflect the differential access of exogenous 5HT and endogenous 5HT (released by tail nerve stimulation) to the SN cell body and synaptic terminals, respectively. 相似文献
170.
Combinators and structurally free logic 总被引:2,自引:0,他引:2