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   2643篇
  免费   72篇
  国内免费   2篇
  2019年   26篇
  2018年   34篇
  2017年   47篇
  2016年   55篇
  2015年   29篇
  2014年   36篇
  2013年   317篇
  2012年   73篇
  2011年   79篇
  2010年   44篇
  2009年   53篇
  2008年   67篇
  2007年   65篇
  2006年   75篇
  2005年   87篇
  2004年   71篇
  2003年   71篇
  2002年   70篇
  2001年   34篇
  2000年   30篇
  1999年   43篇
  1998年   54篇
  1997年   36篇
  1996年   41篇
  1995年   37篇
  1994年   35篇
  1993年   37篇
  1992年   31篇
  1991年   37篇
  1990年   34篇
  1989年   45篇
  1988年   35篇
  1987年   32篇
  1986年   30篇
  1984年   43篇
  1983年   35篇
  1982年   47篇
  1981年   37篇
  1980年   41篇
  1979年   42篇
  1978年   45篇
  1977年   36篇
  1976年   39篇
  1975年   35篇
  1974年   43篇
  1973年   37篇
  1971年   26篇
  1969年   33篇
  1968年   26篇
  1967年   25篇
排序方式: 共有2717条查询结果,搜索用时 15 毫秒
931.
Rats with selective lesions of the nucleus basalis magnocellularis (NBM) and sham-lesion control animals were tested in an operant appetitive-to-aversive transfer task. We hypothesized that NBM lesions would not affect performance in the appetitive phase, but that performance would be impaired during subsequent transfer to the aversive phase of the task. Additional groups of NBM lesion and control rats were tested in the avoidance condition only, where we hypothesized that NBM lesions would not disrupt performance. These hypotheses were based, on the argument that the NBM is not necessary for simple association learning that does not tax attention. Both the appetitive phase of the transfer task and the avoidance only task depend only on simple associative learning and are argued not to tax attention. Consequently, performance in these tasks was predicted to be spared following NBM lesions. Complex, attention-demanding associative learning, however, is argued to depend on the NBM. Performance, in the aversive phase of the transfer task is both attentionally demanding and associatively more complex than in either the appetitive or aversive tasks alone; thus, avoidance performance in the NBM lesion group was predicted to be impaired following transfer from prior appetitive conditioning. Results supported our hypotheses, with the NBM lesion group acquiring the appetitive response normally, but showing impaired performance following transfer to the aversive conditioning phase of the transfer task. Impairments were not attributable to disrupted avoidance learning per se, as avoidance behavior was normal in the NBM lesion group tested in the avoidance condition only.  相似文献   
932.
This investigation focuses on the relations between prior beliefs, methodological concepts, and college students' (N=211) scientific reasoning in different problem contexts. Participants were presented with exercises that described the method and results of experiments, and were asked to draw conclusions about the causal status of variables that violated their prior beliefs. Participants drew conclusions in both abstract (i.e. recommend a conclusion for the fictional experimenter), and personal settings (i.e. draw their own conclusions about the phenomenon). Participants' recommendations for the hypothetical experimenter were predicted by their understanding of two methodological concepts: the function of empirical evidence and experimental control. Students' personal conclusions were predicted by their prior beliefs and their appreciation of the objectivity of inquiry. Thus, even when students understand in the abstract how data should relate to scientific conclusions, prior beliefs often take precedence in their own conclusions, especially when they do not understand the issue of objectivity. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   
933.
The purpose of this study was to provide a reexamination of the NCAA (National Collegiate Athletic Association) News and the extent to which the publication provides equitable coverage to women and women's teams. To do so, 5,745 paragraphs and 1,086 photographs from 24 issues (12 issues in 1999, 12 issues in 2001) were coded for (a) gender, (b) size, (c) location, and (d) content. Results were then compared to a standard (i.e., the proportion of female athletes competing in NCAA intercollegiate athletics). Results indicate that coverage in the NCAA News was more representative, with respect to the amount of text and number of photographs, than it was in 1988 and 1991.  相似文献   
934.
The Eastern Orthodox Church has encountered Islam from the first decades of its appearance and they interacted in a variety of ways. Most frequently the meeting took the form of polemical clash and confrontation. However, in the many centuries of silent coexistence, it was often expressed in a concrete form of dialogue that sought to define the differences and the positions of the two religious forms and experiences. The present study focuses on the contemporary academic dialogues between Orthodox Christianity and Islam which began in the spring of 1985 at Holy Cross Greek Orthodox School of Theology in Brookline, MA. These dialogues were initiated by the Ecumenical Patriarchate of Constantinople and further meetings were held under its auspices in Chambésy, Constantinople (Istanbul), Athens, and Amman. This article presents the issues discussed, pointing to the fact that peaceful coexistence and justice may only prevail on a basis of mutual knowledge and understanding of the other.  相似文献   
935.
Four groups of undergraduates (half of each gender) experienced a movement along a corridor containing three distinctive objects, in a virtual environment (VE) with wide-screen projection. One group simulated walking along the virtual corridor using a proprietary step-exercise device. A second group moved along the corridor in conventional flying mode, depressing a keyboard key to initiate continuous forward motion. Two further groups observed the walking and flying participants, by viewing their progress on the screen. Participants then had to walk along a real equivalent but empty corridor, and indicate the positions of the three objects. All groups underestimated distances in the real corridor, the greatest underestimates occurring for the middle distance object. Males' underestimations were significantly lower than females' at all distances. However, there was no difference between the active participants and passive observers, nor between walking and flying conditions.  相似文献   
936.
The identification of jurisdictional drug use patterns is critical to counselors who address substance abuse proactively. In the current study, heroin use data were analyzed from adult arrestees who were surveyed between 1990 and 1997 through the Arrestee Drug Abuse Monitoring program.  相似文献   
937.
Two methods of monitoring the circadian rhythm of activity in rodents: (1) an activity wheel cage, which detects the number of wheel revolutions, and (2) an internal radio transmitter, which records gross motor activity (GMA) of the animal, were compared in both normal circadian cycles and during the development of activity-stress ulcers. Rats were implanted with a biotelemetry transmitter that detected GMA and body temperature (BT) and placed in activity wheel cages. A 12 hour/12 hour light/dark cycle was maintained throughout the experiment. Subjects were subdivided into two groups: (1) unlimited access to activity wheel (AW) cages and (2) locked activity wheel (LW) cages. Following an ad-libitum habituation period, animals were allowed food access for 1 hour/day during the light. In the habituation period, the animals showed higher GMA and BT during the dark phase when housed in AW cages than in LW cages. Both GMA and number of wheel revolutions increased dramatically after the onset of food restriction for the AW animals. There was a deleterious drop in BT in AW animals as the food-restricted period continued and a significant correlation existed between severity of ulcerations and BT. The findings of this experiment demonstrate that the activity wheel imposes an alternation of the circadian cycle, which, in turn, influences rhythmicity through reentrainment. Additionally, in the activity-stress paradigm, a significant drop in BT correlates with severity of ulcerations. A disrupted circadian cycle, involving hypothermia, is proposed as the mechanism underlying the demise of animals in the activity-stress paradigm.  相似文献   
938.
This meta‐analysis investigated the possibility that gender differences in aggression, and the variability in these differences, are a function of gender differences in the regulation of arousal generated in emotionally evocative contexts. The sample of studies for this analysis was based on an exhaustive search of the relevant research reports from 1965–1999. Studies were excluded from the sample if they were case studies; investigated spousal/familial or societal violence, war, suicide, or political violence; involved clinical or deviant participants; included fewer than 10 participants; included all male, all female, all non‐Caucasian, or non‐US/non‐Canadian participants. Based on previous evidence that males may be more easily aroused by aggressive‐relevant emotional stimuli than females, and that males may have more difficulty regulating emotionally arousing states than females, we hypothesized that the magnitude of the gender differences in aggression would covary, in a nonlinear manner, with the emotional evocativeness of the study context. Consistent with our hypothesis, the magnitude of gender differences in aggression was relatively small in research contexts that appeared to produce no or large increments in emotional arousal and larger (favoring males) in contexts that appeared to produce small or medium increments in emotional arousal. Aggr. Behav. 28:366–393, 2002. © 2002 Wiley‐Liss, Inc.  相似文献   
939.
To study the relationship between cancer and emotional adjustment, investigation of situation-specific coping behaviors with respect to narrowly defined Stressors has recently been promoted. The development and validation of shorter instruments, designed to facilitate completion by clinical populations, has also been recommended. The current study examined the coping skills used by French-Canadian women undergoing radiation therapy for breast cancer. A factor analysis of the 28-item shortened COPE (Carver, Scheier, & Weintraub, 1989) yielded the following eight factors: disengagement, self-distraction, active coping, using emotional support from husband/ partner, using emotional support from friends, turning to religion, humor, and substance use. The test-retest and Cronbach alpha internal consistency reliability coefficients of the French-Canadian shortened COPE were actually higher than those observed in the full-length version of the instrument. In addition, the eight factor-based scores correlated in a theoretically meaningful manner with existing measures of coping skills with illness (Coping with Health Injuries and Problems; CHIP) and mood disturbance (Profile of Mood States; POMS), thus suggesting good construct convergent and concurrent criterion validity. In particular, the disengagement COPE scale was correlated highly with anxiety, depression, and anger. While further validation is recommended, the results show promise for the shortened COPE in assessing coping in women with breast cancer, and also provide continued evidence for the notion that specific coping skills are associated with particular mood states.  相似文献   
940.
In this paper we argue that model selection, as commonly practised in psychometrics, violates certain principles of coherence. On the other hand, we show that Bayesian nonparametrics provides a coherent basis for model selection, through the use of a ‘nonparametric’ prior distribution that has a large support on the space of sampling distributions. We illustrate model selection under the Bayesian nonparametric approach, through the analysis of real questionnaire data. Also, we present ways to use the Bayesian nonparametric framework to define very flexible psychometric models, through the specification of a nonparametric prior distribution that supports all distribution functions for the inverse link, including the standard logistic distribution functions. The Bayesian nonparametric approach provides a coherent method for model selection that can be applied to any statistical model, including psychometric models. Moreover, under a ‘non‐informative’ choice of nonparametric prior, the Bayesian nonparametric approach is easy to apply, and selects the model that maximizes the log likelihood. Thus, under this choice of prior, the approach can be extended to non‐Bayesian settings where the parameters of the competing models are estimated by likelihood maximization, and it can be used with any psychometric software package that routinely reports the model log likelihood.  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