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   2715篇
  免费   226篇
  国内免费   3篇
耳鼻咽喉   25篇
儿科学   116篇
妇产科学   47篇
基础医学   307篇
口腔科学   87篇
临床医学   387篇
内科学   437篇
皮肤病学   63篇
神经病学   353篇
特种医学   116篇
外科学   266篇
综合类   22篇
预防医学   352篇
眼科学   15篇
药学   175篇
中国医学   6篇
肿瘤学   170篇
  2023年   40篇
  2022年   61篇
  2021年   99篇
  2020年   65篇
  2019年   114篇
  2018年   103篇
  2017年   84篇
  2016年   72篇
  2015年   89篇
  2014年   103篇
  2013年   162篇
  2012年   225篇
  2011年   181篇
  2010年   89篇
  2009年   69篇
  2008年   144篇
  2007年   112篇
  2006年   106篇
  2005年   97篇
  2004年   99篇
  2003年   85篇
  2002年   93篇
  2001年   36篇
  2000年   28篇
  1999年   44篇
  1998年   16篇
  1997年   19篇
  1996年   16篇
  1995年   15篇
  1994年   13篇
  1992年   21篇
  1991年   23篇
  1990年   16篇
  1989年   16篇
  1988年   16篇
  1987年   20篇
  1986年   15篇
  1983年   15篇
  1982年   19篇
  1981年   11篇
  1980年   13篇
  1979年   14篇
  1978年   13篇
  1976年   12篇
  1975年   17篇
  1974年   17篇
  1973年   25篇
  1972年   14篇
  1971年   13篇
  1968年   13篇
排序方式: 共有2944条查询结果,搜索用时 31 毫秒
91.
92.
22q11.2 deletion syndrome (22q11DS) has a complex phenotype with more than 180 characteristics, including cardiac anomalies, cleft palate, intellectual disabilities, a typical facial morphology, and mental health problems. However, the variable phenotype makes it difficult to predict clinical outcome, such as the high prevalence of psychosis among adults with 22q11DS (~25–30% vs. ~1% in the general population). The purpose of this study was to investigate whether subtypes exist among people with 22q11DS, with a similar phenotype and an increased risk of developing mental health problems. Physical, cognitive and behavioural data from 50 children and adolescents with 22q11DS were included in a k-means cluster analysis. Two distinct phenotypes were identified: Type-1 presented with a more severe phenotype including significantly impaired verbal memory, lower intellectual and academic ability, as well as statistically significant reduced total brain volume. In addition, we identified a trend effect for reduced temporal grey matter. Type-1 also presented with autism-spectrum traits, whereas Type-2 could be described as having more 22q11DS-typical face morphology, being predominately affected by executive function deficits, but otherwise being relatively high functioning with regard to cognition and behaviour. The confirmation of well-defined subtypes in 22q11DS can lead to better prognostic information enabling early identification of people with 22q11DS at high risk of psychiatric disorders. The identification of subtypes in a group of people with a relatively homogenous genetic deletion such as 22q11DS is also valuable to understand clinical outcomes.  相似文献   
93.
94.
95.
ObjectivesTranscranial magnetic stimulation (TMS) has been extensively used for the treatment of depression, obsessive-compulsive disorder, and certain neurologic disorders. Despite having promising treatment efficacy, the fundamental neural mechanisms of TMS remain understudied.Materials and MethodsIn this study, 15 healthy adult participants received simultaneous TMS and functional magnetic resonance imaging to map the modulatory effect of TMS when it was applied over three different sites in the dorsolateral prefrontal cortex. Independent component analysis (ICA) was used to identify the networks affected by TMS when applied over the different sites. The standard general linear model (GLM) analysis was used for comparison.ResultsICA showed that TMS affected the stimulation sites as well as remote brain areas, some areas/networks common across all TMS sites, and other areas/networks specific to each TMS site. In particular, TMS site and laterality differences were observed at the left executive control network. In addition, laterality differences also were observed at the dorsal anterior cingulate cortex and dorsolateral/dorsomedial prefrontal cortex. In contrast with the ICA findings, the GLM-based results mainly showed activation of auditory cortices regardless of the TMS sites.ConclusionsOur findings support the notion that TMS could act through a top-down mechanism, indirectly modulating deep subcortical nodes by directly stimulating cortical regions.Clinical Trial RegistrationThe Clinicaltrials.gov registration number for the study is NCT03394066.  相似文献   
96.
97.
We examined the associations of different aspects of social support during emergency department (ED) evaluation for an acute cardiac event with perceptions of threat in the ED and subsequent posttraumatic stress symptoms (PSS) in 484 patients. Participants were enrolled in the ED where they reported on their perceptions of threat in the ED. Social support in the ED and PSS were assessed at inpatient bedside or by telephone a median of 3 days later. Positive aspects of social support were not associated with subsequent PSS. Anxiety-provoking social support was significantly associated with increased PSS at follow-up. Greater ED threat perception partially mediated that relationship.  相似文献   
98.
99.
Individualism and collectivism are cultural syndromes that have been associated with adolescent problem behavior in studies conducted in the U.S. and Southeast Asia. However, research investigating the mechanisms of how cultural orientation impacts health risk behaviors has been limited. This study tested a new model explaining the relationship between cultural orientation (i.e., individualism, collectivism) and adolescent problem behavior (i.e., substance use and risky sex) in terms of interpersonal self-regulation (i.e., social self-control). As such, the study is rooted in theories of the role of culture in developing self-regulation. Participants were high school students (N = 716) from the Bashkirtostan Republic of the Russian Federation. Adolescents from the Russian Federation tend to show high prevalence of cigarette smoking and binge drinking. People of the Russian Federation in general are traditionally collectivist in orientation, although increased globalization and post-Soviet capitalism may indicate high individualist values in younger generation Russians. Using path analysis we found that in addition to having direct effects, higher individualism indirectly affected substance use and risky sexual behavior through social self-control and negative life events. Higher collectivism was found to have a direct protective effect on risky sexual behavior and a direct effect on social self-control. However, collectivism was not found to have indirect effects on substance use or risky sexual behavior. Higher individualism appears to function as a risk factor for adolescent problem behavior and this relationship may be mediated by lower social self-control. Culturally-tailored prevention programs utilizing the individualism-collectivism framework may benefit from addressing social self-control.  相似文献   
100.
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