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   2916篇
  免费   86篇
  国内免费   4篇
  2023年   13篇
  2021年   14篇
  2020年   35篇
  2019年   52篇
  2018年   73篇
  2017年   62篇
  2016年   70篇
  2015年   51篇
  2014年   58篇
  2013年   359篇
  2012年   106篇
  2011年   98篇
  2010年   79篇
  2009年   66篇
  2008年   93篇
  2007年   110篇
  2006年   96篇
  2005年   100篇
  2004年   106篇
  2003年   91篇
  2002年   95篇
  2001年   48篇
  2000年   46篇
  1999年   54篇
  1998年   54篇
  1997年   38篇
  1996年   63篇
  1995年   51篇
  1994年   53篇
  1993年   50篇
  1992年   52篇
  1991年   35篇
  1990年   41篇
  1989年   41篇
  1988年   33篇
  1987年   38篇
  1986年   34篇
  1985年   49篇
  1984年   33篇
  1983年   45篇
  1982年   39篇
  1981年   32篇
  1980年   33篇
  1979年   19篇
  1978年   26篇
  1977年   22篇
  1976年   18篇
  1975年   16篇
  1974年   22篇
  1973年   17篇
排序方式: 共有3006条查询结果,搜索用时 15 毫秒
231.
The commitment of transplant physicians to protect the physical and psychological health of potential donors is fundamental to the process of living donor organ transplantation. It is appropriate that strict regulations to govern an individual's decision to donate have been developed. Some may argue that adherence to such regulations creates a doctor-patient relationship that is rooted in paternalism, which is in drastic contrast with a doctor-patient relationship that is rooted in patients' autonomy, characteristic of most other operative interventions. In this article we analyze the similarities between cosmetic plastic surgery and living donor surgery as examples of surgeries governed by different ethical principles. It is interesting that, while the prevailing ethical approach in living donor surgery is based on paternalism, the ethical principle guiding cosmetic surgery is respect for patients' autonomy. The purpose of this article is not to criticize either practice, but to suggest that, given the similarities between the two procedures, both operative interventions should be guided by the same ethical principle: a respect for patients' autonomy. We further suggest that if living organ donation valued donors' autonomy as much as cosmetic plastic surgery does, we might witness a wider acceptance of and increase in living organ donation.  相似文献   
232.
This brief report describes results from an evaluation of NAMI Basics, a peer-delivered family education program for family caregivers of children and adolescents with mental illness. Over six classes, family members are given information (e.g. education about mental illness and treatments), skills training (e.g. family communication skills) and advocacy support. We report data from 36 caregivers who completed pre and posttest instruments measuring self-care, empowerment, and family problem-solving and communication skills. Results showed significant improvements in self-care, empowerment, and “incendiary” family communication after participation in the program. Results suggest that NAMI Basics may improve both parental functioning and familial processes. Implications and future directions are discussed.  相似文献   
233.
In the aftermath of several school shooting incidents in recent years, students’ perceptions of unsafe schools has been a major concern for parents, teachers, school officials, school practitioners, and policy-makers. Using Bronfenbrenner’s ecological systems framework, we examined the micro-, meso-, and exosystem level factors associated with perceptions of unsafe school environments in a nationally representative sample of 10- to 15-year-old youth in the United States. We found that for the socio-demographic characteristics, students who were older, male, and poor had increased risks of perceiving higher levels of unsafe school environments. Within the microsystem of the family, our results indicate that parent-youth discussions of school activities/events decreased the risk of students perceiving unsafe schools. All of the school environment variables—ease of making friends, teachers’ involvement, observed weapon carrying, and school rule enforcement—were related in the expected direction to students’ perceiving their schools as unsafe. At the mesosystem level, findings from our study demonstrate that variables measuring parental school involvement were unrelated to perceptions of school safety. Finally, at the exosystem level, we found that students’ perceptions of residing in a safer neighborhood and residence in a non-central city metropolitan area, compared with a central city, decreased the odds of perceiving school environments as unsafe. School policy and practice implications are discussed.  相似文献   
234.
Parkinson's disease (PD) is a progressive neurodegenerative disease primarily characterised by motor symptoms. However, another feature of PD which is receiving increasing attention is the phenomenon of impulse control disorders (ICDs), such as pathological gambling. To date, research into ICDs in PD has centred on a biomedical model of cause, related to the effects of dopamine replacement therapy. However, there are several areas of discrepancy in the current biomedical account of ICDs in PD. In addition, we argue that social and psychological factors also need to be considered to achieve a more complete understanding of the phenomenon. We present a novel conceptual model which combines biomedical and psychosocial factors in the genesis of ICDs in PD and use the model to identify a number of potential treatment intervention points and to highlight important outstanding questions concerning the inter-relationship between psychosocial and biomedical factors in the genesis of ICDs in PD.  相似文献   
235.
Little is known about positive development across the transition from adolescence to young adulthood. The purpose of this paper was to use longitudinal data from a large community sample, the Australian Temperament Project, to investigate prospective associations between positive development at age 19?C20?years and changes in social, health, and behavioral outcomes at 23?C24?years. Data from 890 young adults (61.7% women) were analyzed using path analysis. Emotional health, physical well-being, friendship quality, reduced antisocial behavior, and positive development in young adulthood were predicted by higher levels of positive development in late adolescence, after controlling for baseline levels of respective outcomes, gender, and family socioeconomic status. Parent relationship quality and alcohol use were not significantly predicted. Based on these findings, interventions promoting positive development during adolescence should be investigated as a potential means of yielding positive social, health, and behavioral consequences well into young adulthood.  相似文献   
236.
Autobiographical memory research documents increased access in the number of memories recalled by emerging adults (ages 18–25) with stable, clearly defined self-concepts. Very little research has examined the relationship between self-concept clarity and the episodic and semantic components of emerging adults’ autobiographical recollections. This study examined the relationship between episodic and semantic autobiographical memory and self-concept clarity in 100 undergraduate students. Contrary to previous findings, which indicated that stable self-beliefs may be used to facilitate access to episodic memories, the results suggested that self-concept clarity may not be associated with memory specificity. Instead, self-concept clarity was associated with recall of events involving cooperative social interactions. Results further showed that older age was associated with higher SCC. The implications of these results are discussed within the context of the theoretical literature concerning the relation between autobiographical memory and the development of the self-concept during emerging adulthood.  相似文献   
237.
Interactive display systems give users flexibility to tailor their visual displays to different tasks and situations. However, in order for such flexibility to be beneficial, users need to understand how to tailor displays to different tasks (to possess "metarepresentational competence"). Recent research suggests that people may desire more complex and realistic displays than are most effective (Smallman & St. John, 2005). In Experiment 1, undergraduate students were tested on a comprehension task with geospatial displays (weather maps) that varied in the number of extraneous variables displayed. Their metacognitive judgments about the relative effectiveness of the displays were also solicited. Extraneous variables slowed response time and increased errors, but participants favored complex maps that looked more realistic about one third of the time. In Experiment 2, the eye fixations of undergraduate students were monitored as they performed the comprehension task. Complex maps that looked more realistic led to more eye fixations on both task-relevant and task-irrelevant regions of the displays. Experiment 3 compared performance of experienced meteorologists and undergraduate students on the comprehension and metacognitive tasks. Meteorologists were as likely as undergraduate students to prefer geographically complex (realistic) displays and more likely than undergraduates to opt for displays that added extraneous weather variables. However, meteorologists were also slower and less accurate with complex than with simple displays. This work highlights the importance of empirically testing principles of visual display design and suggests some limits to metarepresentational competence.  相似文献   
238.
Objective: To empirically identify the appropriate symptom threshold for hyperactivity-impulsivity for diagnosis of ADHD in adults. Method: Participants were 88 adults (M [SD] age = 41.69 [11.78] years, 66% female, 16% minority) meeting formal DSM-IV criteria for ADHD combined or predominantly inattentive subtypes based on a structured diagnostic interview keyed to DSM-IV (Conners' Adult ADHD Diagnostic Interview for DSM-IV [CAADID]). All participants also completed the Conners' Adult ADHD Rating Scale (CAARS), which was normed on the general adult population and includes subscales for DSM-IV inattentive and DSM-IV hyperactive-impulsive symptoms. A T-score threshold of 65 (at least 1.5 SD above population mean) on the CAARS DSM-IV hyperactive-impulsive dimension was used to identify participants with empirically elevated symptom severity. Results: Of 88 participating adults, 48 (55%) had a T-score of at least 65 (1.5 SD) on the CAARS DSM-IV Hyperactive-Impulsive scale. Of these, only 25 (52%) met the DSM-IV cutoff of six hyperactive-impulsive symptoms on the CAADID. Thus, approximately half of those who reported empirically elevated hyperactive-impulsive complaints on the CAARS did not concurrently meet the six-symptom DSM-IV cutoff on the CAADID. An alternative cutoff of four hyperactive-impulsive symptoms on the CAADID captured 39 (81%) cases identified by the CAARS. Conclusion: In adults, mandating at least six hyperactive-impulsive symptoms excludes a significant percentage (almost half) of adults who are at least 1.5 SD above the population mean on a dimensional measure of hyperactivity-impulsivity. These data provide a compelling basis for lowering the symptom threshold of hyperactivity-impulsivity for adults in the DSM-5.  相似文献   
239.
Although the study of brain states is an old one in neuroscience, there has been growing interest in brain state specification owing to MRI studies tracing brain connectivity at rest. In this review, we summarize recent research on three relatively well-described brain states: the resting, alert, and meditation states. We explore the neural correlates of maintaining a state or switching between states, and argue that the anterior cingulate cortex and striatum play a critical role in state maintenance, whereas the insula has a major role in switching between states. Brain state may serve as a predictor of performance in a variety of perceptual, memory, and problem solving tasks. Thus, understanding brain states is critical for understanding human performance.  相似文献   
240.
This paper examines the effects of group performance anxiety on the attrition of women and minorities from science, math, and engineering majors. While past research has relied primarily on the academic deficits and lower socioeconomic status of women and minorities to explain their absence from these fields, we focus on the impact of stereotype threat—the anxiety caused by the expectation of being judged based on a negative group stereotype. Using data from the National Longitudinal Survey of Freshmen, our findings indicate that minorities experience stereotype threat more strongly than whites, although women do not suffer from stereotype threat more than men. Our findings also reveal that stereotype threat has a significant positive effect on the likelihood of women, minorities, and surprisingly, white men leaving science, technology, engineering and math majors.  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