全文获取类型
收费全文 | 16877篇 |
免费 | 803篇 |
国内免费 | 15篇 |
专业分类
17695篇 |
出版年
2021年 | 132篇 |
2020年 | 225篇 |
2019年 | 241篇 |
2018年 | 356篇 |
2017年 | 359篇 |
2016年 | 366篇 |
2015年 | 281篇 |
2014年 | 308篇 |
2013年 | 1318篇 |
2012年 | 569篇 |
2011年 | 644篇 |
2010年 | 371篇 |
2009年 | 349篇 |
2008年 | 472篇 |
2007年 | 451篇 |
2006年 | 393篇 |
2005年 | 334篇 |
2004年 | 338篇 |
2003年 | 318篇 |
2002年 | 323篇 |
2001年 | 700篇 |
2000年 | 699篇 |
1999年 | 461篇 |
1998年 | 180篇 |
1997年 | 173篇 |
1996年 | 138篇 |
1995年 | 135篇 |
1993年 | 138篇 |
1992年 | 360篇 |
1991年 | 321篇 |
1990年 | 345篇 |
1989年 | 334篇 |
1988年 | 317篇 |
1987年 | 288篇 |
1986年 | 310篇 |
1985年 | 298篇 |
1984年 | 235篇 |
1983年 | 200篇 |
1979年 | 190篇 |
1978年 | 161篇 |
1975年 | 187篇 |
1974年 | 241篇 |
1973年 | 197篇 |
1972年 | 203篇 |
1971年 | 167篇 |
1970年 | 149篇 |
1969年 | 198篇 |
1968年 | 202篇 |
1967年 | 161篇 |
1966年 | 182篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
971.
Strategic attention deployment for delay of gratification in working and waiting situations 总被引:3,自引:0,他引:3
Two studies examined whether the detrimental effects of attention to rewards on delay of gratification in waiting situations holds-or reverses-in working situations. In Study 1, preschoolers waited or worked for desired delayed rewards. Delay times increased when children worked in the presence of rewards but, as predicted, this increase was due to the distraction provided by the work itself. not because attention to rewards motivated children to sustain work. Analysis of spontaneous attention deployment showed that attending to rewards reduces delay time regardless of the working or waiting nature of the task. Fixing attention on rewards was a particularly detrimental strategy regardless of the type of task. Study 2 showed that when the work is not engaging, however, attention to rewards can motivate instrumental work and facilitate delay of gratification as long as attention deployment does not become fixed on the rewards. 相似文献
972.
Using the paradigm of habituation learning in the open field, we tested the effects of unilateral microinjections of the agonist nicotine (8.0, 40.0, and 80.0 microg) and the nicotine receptor antagonist mecamylamine (0.1, 1.0, 10.0 microg) into the core of the nucleus accumbens. When injected posttrial, that is, immediately after the first exposure to the open field, nicotine dose-dependently enhanced behavioral habituation during the test on the following day, indicating a facilitation of memory, whereas mecamylamine impaired habituation at the highest dose, but not at the two lower doses. When injected 5 h after the learning trial, nicotine (40 microg) and mecamylamine (10 microg) impaired habituation on the subsequent day. A control experiment did not provide evidence for possible proactive effects of mecamylamine. These findings are discussed with respect to the possible behavioral functions of cholinergic, and especially nicotinic, mechanisms in the nucleus accumbens. They may also be relevant for understanding cholinergic-linked psychopathologies such as Alzheimer's disease, since the nucleus accumbens is one of the sites where cholinergic neurons are lost in this neurodegenerative disease. 相似文献
973.
This study had two aims: to test the hypothesis that borderline personality disorder (BPD) patients hold numerous dysfunctional beliefs associated with a variety of Axis II disorders, and to construct a BPD belief scale which captures these beliefs. Beliefs were measured using the Personality Belief Questionnaire (PBQ) which is designed to assess beliefs associated with various personality disorders, although not specifically BPD. Eighty-four BPD patients and 204 patients with other personality disorders (OPD) were randomly split into two study samples. Fourteen PBQ items were found to discriminate BPD from OPD patients in both samples. These items came from the PBQ Dependent, Paranoid, Avoidant, and Histrionic scales and reflect themes of dependency, helplessness, distrust, fears of rejection/abandonment/losing emotional control, and extreme attention-seeking behavior. A BPD beliefs scale constructed from these items showed good internal consistency and diagnostic validity among the 288 study patients. The scale may be used to assist in diagnosis and cognitive therapy of BPD. 相似文献
974.
In a typical conditional discrimination, a target stimulus (X) is reinforced during one feature cue (A-->X+), but not during another feature cue (B-->X-). The present experiments used only a single "feature" cue (a 66-sec tone). On half of the trials, the target stimulus (a 400-msec light) was paired with the reinforcer when the feature-target interval was one duration (e.g., 5 sec). On the remaining trials, the interval was different (e.g., 45 sec), and the target stimulus was presented without the reinforcer. All the animals acquired this temporal discrimination, and subsequent testing with other feature-target intervals yielded generalization-like gradients. These results provide solid evidence that each portion of a feature cue is encoded in a distinctive fashion. Had temporal encoding not occurred, the feature cue would have been just as ambiguous a predictor of the reinforcer as was the target stimulus, and discrimination would not have been possible. The integration of real-time temporal encoding mechanisms into models of conditional discrimination is discussed. 相似文献
975.
Moving Beyond Self‐Report: Implicit Associations about Death/Life Prospectively Predict Suicidal Behavior among Veterans 下载免费PDF全文
Sean M. Barnes PhD Nazanin H. Bahraini PhD Jeri E. Forster PhD Kelly A. Stearns‐Yoder BA Trisha A. Hostetter MPH Geoffrey Smith PsyD Herbert T. Nagamoto MD Matthew K. Nock PhD 《Suicide & life-threatening behavior》2017,47(1):67-77
Reliance on self‐report limits clinicians' ability to accurately predict suicidal behavior. In this study the predictive validity of an objective measure, the death/suicide Implicit Association Test (d/sIAT), was tested among psychiatrically hospitalized veterans. Following acute stabilization, 176 participants completed the d/sIAT and traditional suicide risk assessments. Participants had similar d/sIAT scores regardless of whether they had recently attempted suicide. However, d/sIAT scores significantly predicted suicide attempts during the 6‐month follow‐up above and beyond other known risk factors for suicidal behavior (OR = 1.89; 95% CI: 1.15–3.12; based on 1SD increase). The d/sIAT may augment the accuracy of suicide risk assessment. 相似文献
976.
Positive and Negative Expectations of Hopelessness as Longitudinal Predictors of Depression,Suicidal Ideation,and Suicidal Behavior in High‐Risk Adolescents 下载免费PDF全文
Adam G. Horwitz MS Johnny Berona MS Ewa K. Czyz PhD Carlos E. Yeguez BS Cheryl A. King PhD 《Suicide & life-threatening behavior》2017,47(2):168-176
The relationship between hopelessness and depression in predicting suicide‐related outcomes varies based on the anticipation of positive versus negative events. In this prospective study of adolescents at elevated risk for suicide, we used two Beck Hopelessness Scale subscales to assess the impact of positive and negative expectations in predicting depression, suicidal ideation, and suicidal behavior over a 2‐ to 4‐year period. In multivariate regressions controlling for depression, suicidal ideation, and negative‐expectation hopelessness, positive‐expectation hopelessness was the only significant predictor of depressive symptoms and suicidal behavior. Clinical interventions may benefit from bolstering positive expectations and building optimism. 相似文献
977.
Jim Parkinson Sarah Garfinkel Hugo Critchley Zoltan Dienes Anil K. Seth 《Cognitive, affective & behavioral neuroscience》2017,17(2):252-268
Volitional action and self-control—feelings of acting according to one’s own intentions and in being control of one’s own actions—are fundamental aspects of human conscious experience. However, it is unknown whether high-level cognitive control mechanisms are affected by socially salient but nonconscious emotional cues. In this study, we manipulated free choice decisions to act or withhold an action by subliminally presenting emotional faces: In a novel version of the Go/NoGo paradigm, participants made speeded button-press responses to Go targets, withheld responses to NoGo targets, and made spontaneous, free choices to execute or withhold the response for Choice targets. Before each target, we presented emotional faces, backwards masked to render them nonconscious. In Intentional trials, subliminal angry faces made participants more likely to voluntarily withhold the action, whereas fearful and happy faces had no effects. In a second experiment, the faces were made supraliminal, which eliminated the effects of angry faces on volitional choices. A third experiment measured neural correlates of the effects of subliminal angry faces on intentional choice using EEG. After replicating the behavioural results found in Experiment 1, we identified a frontal-midline theta component—associated with cognitive control processes—which is present for volitional decisions, and is modulated by subliminal angry faces. This suggests a mechanism whereby subliminally presented “threat” stimuli affect conscious control processes. In summary, nonconscious perception of angry faces increases choices to inhibit, and subliminal influences on volitional action are deep seated and ecologically embedded. 相似文献
978.
Roberta L. Klatzky William B. Thompson Jeanine K. Stefanucci Devin Gill D. Kevin McGee 《Psychonomic bulletin & review》2017,24(6):1870-1878
“Vast” is a word often applied to environmental terrain that is perceived to have large spatial extent. This judgment is made even at viewing distances where traditional metric depth cues are not useful. This paper explores the perceptual basis of vast experience, including reliability and visual precursors. Experiment 1 demonstrated strong agreement in ratings of the spatial extent of two-dimensional (2D) scene images by participants in two countries under very different viewing conditions. Image categories labeled “vast” often exemplified scene attributes of ruggedness and openness (Oliva & Torralba, 2001). Experiment 2 quantitatively assessed whether these properties predict vastness. High vastness ratings were associated with highly open, or moderately open but rugged, scenes. Experiment 3 provided evidence, consistent with theory, that metric distance perception does not directly mediate the observed vastness ratings. The question remains as to how people perceive vast space when information about environmental scale is unavailable from metric depth cues or associated scene properties. We consider possible answers, including contribution from strong cues to relative depth. 相似文献
979.
Viral advertising has become a popular form of persuasive communication to promote brands on social media. Extant research on viral advertising has focused mostly on evaluating content characteristics as drivers of virality, but very few studies have examined the potential influence of consumers' personality variables that affect their information processing and subsequent ad‐sharing behavior. By taking a consumer‐centric approach, two experimental studies were conducted to examine how consumer's need for cognition (NFC: high vs. low) interacts with message appeal (emotional vs. informational) used in the branded viral advertisements and extent of brand information (high vs. low brand prominence) present in the branded viral advertisement to influence consumers' intentions to share viral advertisements. As compared with low‐NFC individuals, high‐NFC individuals reported higher sharing intentions for viral ads that use informational appeal and also for an emotional viral ad where brand prominence is high. This finding is consistent with the elaboration likelihood model (ELM). Further, the results of these studies show an interesting finding that contradicts the existing understanding originating from ELM; that is, high‐NFC individuals reported higher sharing intentions for viral ads with an emotional appeal as compared with low‐NFC individuals, even when the brand prominence is low. Possible explanations and implications of the findings are discussed in this paper. 相似文献