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   2017篇
  免费   62篇
  2023年   8篇
  2022年   7篇
  2021年   19篇
  2020年   23篇
  2019年   26篇
  2018年   55篇
  2017年   48篇
  2016年   53篇
  2015年   42篇
  2014年   42篇
  2013年   234篇
  2012年   76篇
  2011年   89篇
  2010年   59篇
  2009年   64篇
  2008年   78篇
  2007年   91篇
  2006年   69篇
  2005年   79篇
  2004年   78篇
  2003年   71篇
  2002年   69篇
  2001年   34篇
  2000年   32篇
  1999年   29篇
  1998年   34篇
  1997年   29篇
  1996年   32篇
  1995年   28篇
  1994年   31篇
  1993年   32篇
  1992年   24篇
  1991年   17篇
  1990年   29篇
  1989年   30篇
  1988年   29篇
  1987年   19篇
  1986年   17篇
  1985年   20篇
  1984年   26篇
  1983年   20篇
  1982年   26篇
  1981年   23篇
  1980年   19篇
  1979年   9篇
  1978年   23篇
  1977年   10篇
  1976年   18篇
  1975年   16篇
  1973年   11篇
排序方式: 共有2079条查询结果,搜索用时 31 毫秒
941.
“The Scaffolding Theory of Aging and Cognition (STAC)”, proposed in 2009, is a conceptual model of cognitive aging that integrated evidence from structural and functional neuroimaging to explain how the combined effects of adverse and compensatory neural processes produce varying levels of cognitive function. The model made clear and testable predictions about how different brain variables, both structural and functional, were related to cognitive function, focusing on the core construct of compensatory scaffolding. The present paper provides a revised model that integrates new evidence about the aging brain that has emerged since STAC was published 5 years ago. Unlike the original STAC model, STAC-r incorporates life-course factors that serve to enhance or deplete neural resources, thereby influencing the developmental course of brain structure and function, as well as cognition, over time. Life-course factors also influence compensatory processes that are engaged to meet cognitive challenge, and to ameliorate the adverse effects of structural and functional decline. The revised model is discussed in relation to recent lifespan and longitudinal data as well as emerging evidence about the effects of training interventions. STAC-r goes beyond the previous model by combining a life-span approach with a life-course approach to understand and predict cognitive status and rate of cognitive change over time.  相似文献   
942.
Anecdotal accounts suggest some patients have experienced negative outcomes as a result of receiving genetics services from non-genetics providers, but empirical evidence of these incidents and their outcomes is limited. This study examined genetic counselors’ perceptions of the occurrence of such incidents in the state of Minnesota. Twenty-five genetic counselors completed an on-line survey and 20 also participated in a semi-structured telephone interview. The interviewees recalled and described 37 specific incidents they perceived as having negative outcomes for patients and/or their families. Inductive and cross-case analysis revealed common themes including: adverse psychosocial effects, inadequate genetic counseling, genetic testing and screening errors, medical mismanagement, negative shifts in attitudes toward medical providers, and unnecessary use of health care resources. Commonly mentioned strategies for preventing/mitigating negative outcomes included: educational outreach and awareness programs for medical providers and the general public, standardized testing and screening processes, and implementing mechanisms for reporting and addressing adverse events. Additional findings, practice and policy implications, and research recommendations are discussed.  相似文献   
943.
Preimplantation genetic diagnosis (PGD) is an innovative prenatal testing option because the determination of whether a genetic disorder or chromosomal abnormality is evident occurs prior to pregnancy. However, PGD is not covered financially under the majority of private and public health insurance institutions in the United States, leaving couples to decide whether PGD is financially feasible. The aim of this qualitative study was to understand the role of finances in the decision-making process among couples who were actively considering PGD. In-depth, semi-structured interviews were completed with 18 genetic high-risk couples (36 individual partners). Grounded theory guided the analysis, whereby three themes emerged: 1) Cost is salient, 2) Emotions surrounding affordability, and 3) Financial burden and sacrifice. Ultimately, couples determined that the opportunity to avoid passing on a genetic disorder to a future child was paramount to the cost of PGD, but expressed financial concerns and recognized financial access as a major barrier to PGD utilization.  相似文献   
944.
The purpose of this study was to examine rates of child abuse and neglect reports following a community implementation of Parent–Child Interaction Therapy (PCIT), an evidence-supported intervention for the prevention of maltreatment. Among a group of families receiving PCIT, predictors of reports were examined including family demographics, course of treatment, changes in clinical measures, and caregiver report for prior maltreatment victimization and perpetration. Participants (n = 120) included families at-risk for future maltreatment with and without prior maltreatment history. Agency case records were linked with state administrative records of child welfare reports. Time to follow-up ranged from 13 to 40 months. Bivariate and multivariate survival analyses were used to model risk for a later report. During the follow-up period, 12.5 % of families had a report for physical abuse or neglect. Reports of prior victimization as a child and prior perpetration as an adult were strong predictors of a report of perpetration after PCIT. Dosage of PCIT and change in clinical measures did not increase risk for a later report. PCIT can be an effective intervention for preventing maltreatment. Family history of child welfare involvement is a prominent factor in assessing risk for future involvement.  相似文献   
945.
Prior research evaluating health-related quality of life (HRQOL) among pediatric patients with internal cardiac devices has primarily focused on children with cardiac defibrillators, with scant attention devoted to pacemaker recipients. Social support has been conceptualized as a protective factor that partially accounts for differences in HRQOL. This study compares the HRQOL of children with pacemakers with that of healthy children, and examines associations between HRQOL and social support. Twenty-seven pediatric pacemaker recipients completed measures of HRQOL and social support. Their parents also completed measures of child HRQOL. High concordance was found for child and parent-proxy reports of child HRQOL. Children with pacemakers and their parents both reported relatively low child HRQOL when compared to published normative data for healthy children and parents of healthy children. Family and friends emerged as the sources of support positively associated with the greatest number of HRQOL domains. In conclusion, these findings suggest that pediatric pacemaker recipients experience lower levels of HRQOL compared to healthy peers, and that social support from those closest to the child is associated with their perceived HRQOL.  相似文献   
946.
The present study investigated the relation between reaction to negative stimuli and memory for stimuli. The relation was further investigated using as a framework individuals’ affective temperaments (AFTs). Eighty adolescents participated in the study. The AFTs are based on selfreported affect and categorizes individuals in four temperaments: self-actualizing, high affective, low affective and self-destructive. Reaction to negative stimuli was measured by interpretation of specific words in a short story. Two days later, participants were presented with a list of words and asked which of them were present in the short story. Individuals’ AFTs were expected to predict the promotion of pleasure or the prevention of displeasure. On a general level, reaction to negative stimuli predicted memory for negative, positive and neutral words. At an individual level, self-actualizers and high affectives’ negative reaction predicted the memory of positive words (i.e., promotion). In contrast, low affectives’ negative and positive reaction predicted the memory of neutral words (i.e., prevention).  相似文献   
947.
Laboratory animals should be provided with enrichment objects in their cages; however, it is first necessary to test whether the proposed enrichment objects provide benefits that increase the animals’ welfare. The two main paradigms currently used to assess proposed enrichment objects are the choice test, which is limited to determining relative frequency of choice, and consumer demand studies, which can indicate the strength of a preference but are complex to design. Here, we propose a third methodology: a runway paradigm, which can be used to assess the strength of an animal’s motivation for enrichment objects, is simpler to use than consumer demand studies, and is faster to complete than typical choice tests. Time spent with objects in a standard choice test was used to rank several enrichment objects in order to compare with the ranking found in our runway paradigm. The rats ran significantly more times, ran faster, and interacted longer with objects with which they had previously spent the most time. It was concluded that this simple methodology is suitable for measuring rats’ motivation to reach enrichment objects. This can be used to assess the preference for different types of enrichment objects or to measure reward system processes.  相似文献   
948.
Around the end of the first year of life, infants develop a social referencing ability – using emotional information from others to guide their own behavior. Much research on social referencing has focused on changes in behavior in response to emotional information. The present study was an investigation of the changes in neural responses that underlie social referencing behavior, reflected in event‐related potentials (ERPs). Twenty‐six 12‐month‐olds participated in a single‐session visit in which ERPs were recorded both immediately before and after a behavioral intervention in which infants' caregivers provided positive, negative or neutral information about each of three stimuli (ERP data available for = 17). After the intervention, infants devoted more neural resources to processing negative versus neutral and positive information, as observed in early and late positive‐going components. Changes in neural responses from the pre‐ to post‐intervention recordings clarify this observation, indicating a sustained response in the negative and positive conditions, and a decrease in the neutral condition, suggesting an attenuation effect in the neutral condition. Further, infants who attended most to the objects in the behavioral intervention showed increased neural responses in the negative condition and decreased responses in the positive condition. Taken together, these findings suggest that infants' neural responses are differentially affected by positive, negative and neutral information. Furthermore, the findings highlight the importance of measuring the change in neural responses to better interpret post‐experience responses.  相似文献   
949.
Picture book reading is a very common form of interaction between parents and very young children. Here we explore to what extent young children transfer novel information between picture books and the real world. We report that 15- and 18-month-olds can extend newly learned labels both from pictures to objects and from objects to pictures. However, the degree to which they do so is affected by iconicity—how much the objects and pictures resemble one another. The children in these studies more often extended the labels between picture and object when realistic photographs and drawings were involved than less realistic cartoons. These results show that higher levels of perceptual similarity between symbol and referent make the referential relation more transparent, thereby helping children transfer information between them. Thus, the educational function of early picture book interactions may best be served with realistic illustrations.  相似文献   
950.
Police officers make life-or-death shooting decisions in complex situations under extreme time pressure. If officers make a mistake, there are dire consequences—they could kill an innocent or be killed themselves. In contrast to prior work's near-exclusive focus on suspect race, the present study examined features of methodology, officers, suspects, and neighborhoods that may affect officers’ shooting decisions. Empirical exploration of officers’ shooting decisions and mistakes is still in its infancy, and given the seriousness and importance of this phenomenon—and the potential for this research to inform policy decisions—additional research is needed.  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