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   4216篇
  免费   154篇
  国内免费   2篇
  2023年   17篇
  2021年   30篇
  2020年   66篇
  2019年   81篇
  2018年   69篇
  2017年   106篇
  2016年   128篇
  2015年   85篇
  2014年   104篇
  2013年   456篇
  2012年   164篇
  2011年   173篇
  2010年   115篇
  2009年   104篇
  2008年   138篇
  2007年   182篇
  2006年   166篇
  2005年   163篇
  2004年   164篇
  2003年   156篇
  2002年   135篇
  2001年   68篇
  2000年   75篇
  1999年   84篇
  1998年   70篇
  1997年   57篇
  1996年   56篇
  1995年   69篇
  1994年   62篇
  1993年   52篇
  1992年   52篇
  1991年   38篇
  1990年   48篇
  1989年   31篇
  1988年   37篇
  1987年   43篇
  1986年   37篇
  1985年   48篇
  1984年   61篇
  1983年   58篇
  1982年   68篇
  1981年   57篇
  1980年   47篇
  1979年   47篇
  1978年   48篇
  1977年   37篇
  1976年   38篇
  1975年   31篇
  1974年   37篇
  1973年   26篇
排序方式: 共有4372条查询结果,搜索用时 15 毫秒
971.
This study aimed to compare primary and secondary caregiver QOL within families of children with asthma and determine the potential importance of including secondary caregiver QOL in clinical and research settings. Participants included 118 families of children with asthma that had primary and secondary caregivers. Families completed measures in a single research session. Caregivers reported on QOL, psychological functioning, and family burden; children completed a measure of QOL. Child lung function was determined from objective spirometry. Adherence to prescribed controller medication was measured for 6 weeks following the research visit. Primary caregiver QOL was significantly lower than secondary caregiver QOL (Mean overall QOL of 5.85 versus 6.17, p < .05). Better medication adherence was associated with higher primary caregiver QOL (ρ = .22, p = .02); secondary caregiver QOL, not primary caregiver QOL, was positively associated with child QOL (ρ = .20, p = .03). Families with discrepant QOL scores between caregivers (difference in scores of at least .50) were characterized by more family burden and primary caregiver psychological symptoms. Differences in QOL scores between caregivers may be a reflection of primary caregivers’ greater investment in daily asthma management. In families reporting low burden and few psychological difficulties in the primary caregiver, QOL assessments from either caregiver may may be informative and representative of how parents are adapting to child asthma. In families experiencing high levels of burden or more primary caregiver psychological difficulties, QOL reports from secondary caregivers may not be as clinically meaningful.  相似文献   
972.
Pathological stress responses are implicated in numerous disorders. Hypothalamic-pituitary-adrenal axis function is influenced by gene-environment interaction, with early-life environmental adversity having long-lasting effects. We examine the evidence that, in humans, these effects are apparent from infancy. We systematically reviewed published findings on cortisol response to a stressor, in 0-5-year-olds already exposed to adversity. Adversity was defined as a negative environmental influence present post-conception. We searched Ovid MEDLINE (1950-May 2010), EMBASE (1980-May 2010) and PsychINFO (1806-May 2010). We included peer-reviewed, English language studies that analysed salivary cortisol before and after a standardised stressor. We identified 30 studies, of which 27 reported a significant effect of adversity on the cortisol response to stress. Six of these demonstrated an effect of prenatal substance exposure. Thirteen studies found that psychosocial adversity increased cortisol reactivity. Three studies reported that cortisol reactivity could be normalised by intervention programmes. The studies were heterogeneous, both in nature of adversity studied and in stressor used, precluding meta-analysis and assessment of publication bias. Our review presents evidence that adversity disrupts the stress response from an early age. Longitudinal studies are required to determine whether effects persist, alter with time, or are reversible with intervention.  相似文献   
973.
This interview study describes the role that participation in the Institute for Faculty Excellence in Judicial Education (IFEJE) played in the personal and professional development of four judges. Judicial education is a relatively new field of adult and continuing professional education. There is limited literature devoted to this area of study outside of the arena of substantive legal or judging topics. Interviews served as the primary data source for this study along with program evaluations, photographs, and e-mail correspondence from Institute participants. The findings revealed that the combined safe environment, challenges, and support participants experienced at the Institute and learning about adult learning helped them: feel less isolated in their work; stretch their normal work boundaries resulting in the completion of projects for which they had great passion; and benefited them as judges, supervisors, teachers, and in other social relationships.  相似文献   
974.
Numerous reports indicate that the incidence of posttraumatic stress disorder (PTSD) in returning OEF/OIF military personnel is creating a significant healthcare challenge. These findings have served to motivate research on how to better develop and disseminate evidence-based treatments for PTSD. Virtual Reality delivered exposure therapy for PTSD has been previously used with reports of positive outcomes. This article details how virtual reality applications are being designed and implemented across various points in the military deployment cycle to prevent, identify and treat combat-related PTSD in OIF/OEF Service Members and Veterans. The summarized projects in these areas have been developed at the University of Southern California Institute for Creative Technologies, a U.S. Army University Affiliated Research Center, and this paper will detail efforts to use virtual reality to deliver exposure therapy, assess PTSD and cognitive function and provide stress resilience training prior to deployment.  相似文献   
975.

Background

The role of glucocorticoids in extinction of traumatic memories has not been fully characterized despite its potential as a therapeutic target for acquired posttraumatic stress disorder (PTSD). The predator stress paradigm allows us to determine whether glucocorticoids mediate the extinction of both context-dependent and context-independent fear memories.

Methods

Male C57BL/6J mice were exposed to a predator (cat) then repeatedly exposed to the predator stress context in the absence of the cat. Context-dependent (associative) fear memory was assessed as suppression of activity during re-exposure to the predator stress context without the cat (extinction trials). Context-independent fear (non-associative) was assessed seven days after extinction trials using measures of hyperarousal and anxiety-like behaviours in environments unlike the predator stress context. To assess the role of glucocorticoids, mice were injected with metyrapone (50 mg/kg) 90 min prior to extinction trials in predator stressed mice and context-dependent and context-independent fear memories were assessed. Finally, metyrapone-treated predator stressed mice were injected with corticosterone (5 or 10 mg/kg) immediately following extinction trials and context-dependent and context-independent fear memories were assessed.

Results

Repeated re-exposure to the predator stress context without the cat present extinguished context-dependent fear memory, and also reduced hyperarousal, a generalized, chronic PTSD-like symptom. We show that extinction of context-independent predator stress-induced hyperarousal is dependent on endogenous glucocorticoids during the extinction trials. Furthermore, the inhibition of extinction by metyrapone on startle amplitude was reduced by exogenous administration of corticosterone following extinction trials. Overall, these data implicate glucocorticoids in the extinction of hyperarousal, a core symptom of PTSD.  相似文献   
976.
Conditioned behavior as observed during classical conditioning in a group of identically treated animals provides insights into the physiological process of learning and memory formation. However, several studies in vertebrates found a remarkable difference between the group-average behavioral performance and the behavioral characteristics of individual animals. Here, we analyzed a large number of data (1640 animals) on olfactory conditioning in the honeybee (Apis mellifera). The data acquired during absolute and differential classical conditioning differed with respect to the number of conditioning trials, the conditioned odors, the intertrial intervals, and the time of retention tests. We further investigated data in which animals were tested for spontaneous recovery from extinction. In all data sets we found that the gradually increasing group-average learning curve did not adequately represent the behavior of individual animals. Individual behavior was characterized by a rapid and stable acquisition of the conditioned response (CR), as well as by a rapid and stable cessation of the CR following unrewarded stimuli. In addition, we present and evaluate different model hypotheses on how honeybees form associations during classical conditioning by implementing a gradual learning process on the one hand and an all-or-none learning process on the other hand. In summary, our findings advise that individual behavior should be recognized as a meaningful predictor for the internal state of a honeybee--irrespective of the group-average behavioral performance.  相似文献   
977.
978.
Steve Cooke 《Res Publica》2011,17(3):261-274
This paper outlines the moral contours of human relationships with companion animals. The paper details three sources of duties to and regarding companion animals: (1) from the animal’s status as property, (2) from the animal’s position in relationships of care, love, and dependency, and (3) from the animal’s status as a sentient being with a good of its own. These three sources of duties supplement one another and not only differentiate relationships with companion animals from wild animals and other categories of domestic animals such as livestock, but they also overlap to provide moral agents with additional reasons for preventing and avoiding harm to companion animals. The paper concludes that not only do owners and bystanders have direct and indirect duties to protect companion animals from harm, but also that these duties have the potential, in some circumstances, to clash with duties owed to the state and fellow citizens.  相似文献   
979.
Face processing undergoes a fairly protracted developmental time course but the neural underpinnings are not well understood. Prior fMRI studies have only examined progressive changes (i.e., increases in specialization in certain regions with age), which would be predicted by both the Interactive Specialization (IS) and maturational theories of neural development. To differentiate between these accounts, the present study also examined regressive changes (i.e., decreases in specialization in certain regions with age), which is predicted by the IS but not maturational account. The fMRI results show that both progressive and regressive changes occur, consistent with IS. Progressive changes mostly occurred in occipital-fusiform and inferior frontal cortex whereas regressive changes largely emerged in parietal and lateral temporal cortices. Moreover, inconsistent with the maturational account, all of the regions involved in face viewing in adults were active in children, with some regions already specialized for face processing by 5 years of age and other regions activated in children but not specifically for faces. Thus, neurodevelopment of face processing involves dynamic interactions among brain regions including age-related increases and decreases in specialization and the involvement of different regions at different ages. These results are more consistent with IS than maturational models of neural development.  相似文献   
980.
Visual attention in driving with visual secondary task is compared for two visual secondary tasks. N = 40 subjects completed a 1 h test drive in a motion-base driving simulator. During the drive, participants either solved an externally paced, highly demanding visual task or a self paced menu system task. The secondary tasks were offered in defined critical and non-critical driving situations. Eye movement behavior was analyzed and compared for both tasks. Before starting the secondary tasks, eye movement behavior shows a smaller standard deviation of gaze as well as longer fixation durations for both tasks. The comparison between the two tasks indicates that drivers use the possibilities the self paced task offers: during the secondary task, they monitor the driving scene with longer fixations and show a greater standard deviation of gaze position. Furthermore, independently of the type of secondary task, drivers adapt their eye movement behavior to the demands of the situation. In critical driving situations they direct a larger proportion of glance time to the driving task. Last, the relation between glance behavior and collisions is analyzed. Results indicate that collisions go together with an inadequate distribution of attention during distraction. The results are interpreted regarding the attentional processes involved in driving with visual secondary tasks. Based on the similarities and differences between the two secondary tasks, a cognitive approach is developed which assumes that the control of attention during distraction is based on a mental situational model of the driving situation.  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