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   2709篇
  免费   231篇
  国内免费   12篇
耳鼻咽喉   11篇
儿科学   95篇
妇产科学   120篇
基础医学   298篇
口腔科学   47篇
临床医学   221篇
内科学   474篇
皮肤病学   19篇
神经病学   225篇
特种医学   278篇
外科学   478篇
综合类   41篇
预防医学   200篇
眼科学   37篇
药学   222篇
肿瘤学   186篇
  2021年   21篇
  2020年   18篇
  2019年   14篇
  2018年   29篇
  2017年   31篇
  2016年   27篇
  2015年   30篇
  2014年   55篇
  2013年   90篇
  2012年   96篇
  2011年   106篇
  2010年   96篇
  2009年   74篇
  2008年   83篇
  2007年   91篇
  2006年   73篇
  2005年   92篇
  2004年   76篇
  2003年   59篇
  2002年   77篇
  2001年   75篇
  2000年   82篇
  1999年   74篇
  1998年   75篇
  1997年   74篇
  1996年   74篇
  1995年   70篇
  1994年   63篇
  1993年   48篇
  1992年   69篇
  1991年   78篇
  1990年   70篇
  1989年   70篇
  1988年   98篇
  1987年   73篇
  1986年   84篇
  1985年   83篇
  1984年   46篇
  1983年   39篇
  1982年   34篇
  1981年   30篇
  1980年   28篇
  1979年   26篇
  1978年   27篇
  1977年   31篇
  1976年   36篇
  1975年   19篇
  1974年   28篇
  1973年   13篇
  1969年   15篇
排序方式: 共有2952条查询结果,搜索用时 343 毫秒
101.
102.

Objectives

Although individuals with posttraumatic stress disorder (PTSD) are at heightened risk for several serious health conditions, research has not examined how having PTSD impacts receipt of invasive procedures that may alleviate these problems. We examined whether PTSD, after controlling for major depression, was associated with odds of receiving common types of major invasive procedures, and whether race, ethnicity, and gender was associated with odds of procedures.

Methods

Veterans Health Administration patients with PTSD and/or depression were age-matched with patients without these disorders. The odds of invasive hip/knee, digestive system, coronary artery bypass graft/percutaneous coronary intervention (CABG/PCI), and vascular procedures during FY2006–2009 were modeled for the full sample of 501,489 patients and for at-risk subsamples with medical conditions alleviated by the procedures examined.

Results

Adjusting for demographic covariates and medical comorbidity, PTSD without depression was associated with decreased odds of all types of procedures (odds ratios [OR] range 0.74–0.82), as was depression without PTSD (OR range 0.59–0.77). In analyses of at-risk patients, those with PTSD only were less likely to undergo hip/knee (OR = 0.78) and vascular procedures (OR = 0.73) but not CABG/PCI. African-Americans and women at-risk patients were less likely to undergo hip/knee, vascular, and CABG/PCI procedures (OR range 0.31–0.82).

Conclusion

With the exception of CABG/PCI among at-risk patients, Veterans with PTSD and/or depression were less likely to undergo all types of procedures examined. Future studies should examine the reasons for this disparity and whether it is associated with subsequent adverse outcomes.  相似文献   
103.

Aim

This systematic review evaluates the accuracy of predictive assessments and investigations used to assist in the diagnosis of cerebral palsy (CP) in preschool‐age children (<5y).

Method

Six databases were searched for studies that included a diagnosis of CP validated after 2 years of age. The validity of the studies meeting the criteria was evaluated using the Standards for Reporting Diagnostic Accuracy criteria. Where possible, results were pooled and a meta‐analysis was undertaken.

Results

Nineteen out of 351 studies met the full inclusion criteria, including studies of general movements assessment (GMA), cranial ultrasound, brain magnetic resonance imaging (MRI), and neurological examination. All studies assessed high‐risk populations including preterm (gestational range 23–41wks) and low‐birthweight infants (range 500–4350g). Summary estimates of sensitivity and specificity of GMA were 98% (95% confidence interval [CI] 74–100%) and 91% (95% CI 83–93%) respectively; of cranial ultrasound 74% (95% CI 63–83%) and 92% (95% CI 81–96%) respectively; and of neurological examination 88% (95% CI 55–97%) and 87% (95% CI 57–97%) respectively. MRI performed at term corrected age (in preterm infants) appeared to be a strong predictor of CP, with sensitivity ranging in individual studies from 86 to 100% and specificity ranging from 89 to 97% There was inadequate evidence for the use of other predictive tools.

Summary

This review found that the assessment with the best evidence and strength for predictive accuracy is the GMA. MRI has a good predictive value when performed at term‐corrected age. Cranial ultrasound is as specific as MRI and has the advantage of being readily available at the bedside. Studies to date have focused on high‐risk infants. The accuracy of these tests in low‐risk infants remains unclear and requires further research.  相似文献   
104.
European Child & Adolescent Psychiatry - Adolescent depression is linked to adult ill-health and functional impairment, but recent research suggests that individual/contextual factors might...  相似文献   
105.
POLG is the human gene that encodes the catalytic subunit of DNA polymerase gamma (Pol gamma), the replicase for human mitochondrial DNA (mtDNA). A POLG Y955C point mutation causes human chronic progressive external ophthalmoplegia (CPEO), a mitochondrial disease with eye muscle weakness and mtDNA defects. Y955C POLG was targeted transgenically (TG) to the murine heart. Survival was determined in four TG (+/-) lines and wild-type (WT) littermates (-/-). Left ventricle (LV) performance (echocardiography and MRI), heart rate (electrocardiography), mtDNA abundance (real time PCR), oxidation of mtDNA (8-OHdG), histopathology and electron microscopy defined the phenotype. Cardiac targeted Y955C POLG yielded a molecular signature of CPEO in the heart with cardiomyopathy (CM), mitochondrial oxidative stress, and premature death. Increased LV cavity size and LV mass, bradycardia, decreased mtDNA, increased 8-OHdG, and cardiac histopathological and mitochondrial EM defects supported and defined the phenotype. This study underscores the pathogenetic role of human mutant POLG and its gene product in mtDNA depletion, mitochondrial oxidative stress, and CM as it relates to the genetic defect in CPEO. The transgenic model pathophysiologically links human mutant Pol gamma, mtDNA depletion, and mitochondrial oxidative stress to the mtDNA replication apparatus and to CM.  相似文献   
106.
Introduction: Adverse drug reactions (ADRs) are an important cause of morbidity and mortality worldwide. They are associated with healthcare costs due to hospital admissions or prolonged length of stay, as well as additional interventions. The aim of this study was to conduct a systematic review of observational studies to evaluate the economic impact of preventable ADRs.

Areas covered: Published observational research investigating the cost of preventable ADRs in Western countries (limited to the USA and European countries).

Expert opinion: Several reviews have been carried out in the field of the ADR epidemiology but fewer reviews have investigated the economic impact of ADRs, and at the time of writing, none has focused on preventable ADRs. The reason why future research should focus on the costs of preventable ADRs is that both the costs and the negative clinical outcomes are preventable, and as such, are a key point of public health policy action. Nevertheless, the present review highlights an important and sobering limitation of published research on the cost of preventable ADRs, of which the major limitation is the heterogeneity in methods and in reporting which limit what can be known through the summarizing work of a systematic review.  相似文献   

107.
108.
109.
110.
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