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   1116篇
  免费   95篇
  国内免费   9篇
耳鼻咽喉   2篇
儿科学   43篇
妇产科学   21篇
基础医学   118篇
口腔科学   32篇
临床医学   116篇
内科学   172篇
皮肤病学   9篇
神经病学   89篇
特种医学   119篇
外科学   224篇
综合类   89篇
预防医学   70篇
眼科学   10篇
药学   54篇
中国医学   1篇
肿瘤学   51篇
  2022年   7篇
  2021年   16篇
  2020年   9篇
  2019年   10篇
  2018年   24篇
  2017年   12篇
  2016年   16篇
  2015年   16篇
  2014年   25篇
  2013年   36篇
  2012年   32篇
  2011年   41篇
  2010年   42篇
  2009年   43篇
  2008年   39篇
  2007年   35篇
  2006年   58篇
  2005年   46篇
  2004年   63篇
  2003年   41篇
  2002年   34篇
  2001年   23篇
  2000年   27篇
  1999年   17篇
  1998年   37篇
  1997年   31篇
  1996年   32篇
  1995年   39篇
  1994年   24篇
  1993年   12篇
  1992年   33篇
  1991年   20篇
  1990年   28篇
  1989年   27篇
  1988年   24篇
  1987年   20篇
  1986年   15篇
  1985年   11篇
  1984年   18篇
  1983年   14篇
  1982年   7篇
  1981年   9篇
  1980年   11篇
  1979年   13篇
  1978年   13篇
  1977年   14篇
  1976年   6篇
  1974年   4篇
  1972年   7篇
  1970年   8篇
排序方式: 共有1220条查询结果,搜索用时 15 毫秒
41.
Cognitive or executive control is a critical mental ability, an important marker of mental illness, and among the most heritable of neurocognitive traits. Two candidate genes, catechol-O-methyltransferase (COMT) and DRD4, which both have a roles in the regulation of cortical dopamine, have been consistently associated with cognitive control. Here, we predicted that individuals with the COMT Met/Met allele would show improved response execution and inhibition as indexed by event-related potentials in a Go/NoGo task, while individuals with the DRD4 7-repeat allele would show impaired brain activity. We used independent component analysis (ICA) to separate brain source processes contributing to high-density EEG scalp signals recorded during the task. As expected, individuals with the DRD4 7-repeat polymorphism had reduced parietal P3 source and scalp responses to response (Go) compared to those without the 7-repeat. Contrary to our expectation, the COMT homozygous Met allele was associated with a smaller frontal P3 source and scalp response to response-inhibition (NoGo) stimuli, suggesting that while more dopamine in frontal cortical areas has advantages in some tasks, it may also compromise response inhibition function. An interaction effect emerged for P3 source responses to Go stimuli. These were reduced in those with both the 7-repeat DRD4 allele and either the COMT Val/Val or the Met/Met homozygous polymorphisms but not in those with the heterozygous Val/Met polymorphism. This epistatic interaction between DRD4 and COMT replicates findings that too little or too much dopamine impairs cognitive control. The anatomic and functional separated maximally independent cortical EEG sources proved more informative than scalp channel measures for genetic studies of brain function and thus better elucidate the complex mechanisms in psychiatric illness.  相似文献   
42.
43.
44.

Background

There is a dearth of studies describing clinical characteristics and outcome of patients who present with mood disorders related to economic recession.

Aims

To describe a cohort of patients admitted with first-episode depression related to the Irish economic recession and compare this cohort with all other first-episode depressives admitted during the same time period (2009–2010).

Methods

A cohort of 137 patients admitted with first-episode depression to an independent university teaching hospital was prospectively identified and followed up from admission over 2 years (mean follow-up 430 days, s.d. 176 days). The cohort was divided into “Celtic Tiger” (patients with first-episode depression secondary to the economic recession) and non-Celtic Tiger control patients (other first-episode depressed patients). Both groups were compared in terms of clinical characteristics at baseline and outcome over follow-up.

Results

The number of admissions due to first depressive episodes were higher in recession years 2009/10 than in pre-recession years 2008/9. Celtic Tiger patients were predominantly male and more severely depressed with more marked suicidal ideation (χ2, p<0.001) than control patients. They were more likely to recover (χ2, p=0.013), less likely to recur (χ2, p<0.001) and had faster time to recovery (log rank, p<0.001) and slower time to full recurrence (log rank, p=0.001). The Celtic Tiger patients spent more time asymptomatic and less time at full and subthreshold depression levels over follow-up.

Limitations

Study setting of centre specializing in affective disorders treatment, retrospective nature of follow-up after initial prospective interview and lack of patient follow-up interview.

Conclusion

The study describes a subgroup of patients with severe depression associated with economic recession with likely high suicide risk but very favourable outcome.  相似文献   
45.
A 12 hour old infant with extensive right ventricular endocardial fibroelastosis presenting with cyanosis and all the clinical features of the hypoplastic right heart syndrome is reported. Anatomically, there were no other associated cardiac defects. Endocardial fibroelastosis of the right ventricle, therefore, must be recognized as another cause of cyanosis in the newborn which may present with all the clinical manifestations of the hypoplastic right heart syndrome.

Although many different pathologic entities can produce the hypoplastic right heart syndrome, clinical and hemodynamic features are similar. Since the major physiologic derangement is inadequate blood flow to the lungs in all conditions included in this syndrome, a palliative shunt procedure to increase pulmonary blood flow is indicated in symptomatic patients, regardless of the exact anatomic diagnosis.  相似文献   

46.
Ankle sprains are the most frequent sport related injuries with involvement of the lateral collateral ligament complex occurring in 85% of cases. Isolated anterior talofibular ligament injury is by far the commonest followed by combined anterior talofibular and calcaneofibular ligament strain. The posterior talofibular ligament is the strongest component of the lateral collateral ligament complex and is injured in severe ankle injury along with the other lateral collateral ligaments. While isolated calcaneofibular ligament strain has been reported, calcaneofibular ligament and posterior talofibular ligament strains with an intact anterior talofibular ligament are rare and reported in cadaveric studies. We present a case of radiologically diagnosed calcaneofibular ligament and posterior talofibular ligament injury and will discuss the anatomy, stress radiography, and magnetic resonance image findings and the mechanism of this particular injury.  相似文献   
47.
48.
Guillain-Barr啨综合征(GBS)和Miller Fisher综合征(MFS)的诊断标准随着临床研究的深入在不断演变。2011年1月,《疫苗》杂志发表了国际疫苗安全性监测Brighton合作组关于GBS/MFS的诊断定义和研究资料收集规范。此文献中未采用"诊断标准"而采用"诊断定义"是因为其主要目的为评价疫苗安全性而制定,而非用于神经科的GBS/  相似文献   
49.
? There is now increasing evidence that diet plays a major role in prostate cancer biology and tumorigenesis. ? In a health conscious society, it is becoming increasingly common for Urologists to be asked about the impact of diet on prostate cancer. ? In the present review, we explore the current evidence for the role of different dietary components and its' effect on prostate cancer prevention and progression. ? A literature search was conducted using PubMed? to identify key studies. ? There was some evidence to suggest that green tea, isoflavones, lycopenes, cruciferous vegetables and omega 3 polyunsaturated fatty acid intake to be beneficial in the prevention and/or progression of prostate cancer. ? There was also evidence to suggest that a high total fat, meat (especially well cooked) and multivitamin intake may be associated with an increased risk of developing prostate cancer. ? To date publications have been highly heterogeneous and variable in quality and design. More robust, high quality research trials are needed to help us understand the complex relationship between diet and prostate cancer.  相似文献   
50.
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