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   1140篇
  免费   84篇
  国内免费   4篇
耳鼻咽喉   48篇
儿科学   41篇
妇产科学   50篇
基础医学   220篇
口腔科学   42篇
临床医学   60篇
内科学   233篇
皮肤病学   28篇
神经病学   122篇
特种医学   60篇
外科学   135篇
综合类   3篇
预防医学   70篇
眼科学   2篇
药学   37篇
肿瘤学   77篇
  2023年   10篇
  2022年   21篇
  2021年   32篇
  2020年   28篇
  2019年   45篇
  2018年   60篇
  2017年   34篇
  2016年   32篇
  2015年   31篇
  2014年   39篇
  2013年   56篇
  2012年   83篇
  2011年   79篇
  2010年   52篇
  2009年   42篇
  2008年   50篇
  2007年   69篇
  2006年   50篇
  2005年   61篇
  2004年   46篇
  2003年   32篇
  2002年   35篇
  2001年   16篇
  2000年   11篇
  1999年   15篇
  1998年   16篇
  1997年   13篇
  1996年   9篇
  1995年   8篇
  1994年   4篇
  1993年   9篇
  1992年   22篇
  1991年   8篇
  1990年   16篇
  1989年   14篇
  1988年   13篇
  1987年   8篇
  1986年   4篇
  1985年   8篇
  1984年   7篇
  1983年   4篇
  1982年   3篇
  1981年   2篇
  1979年   4篇
  1978年   3篇
  1976年   5篇
  1973年   5篇
  1971年   2篇
  1969年   2篇
  1967年   2篇
排序方式: 共有1228条查询结果,搜索用时 15 毫秒
1.

Background

Whether prolonged operative time is an independent risk factor for subsequent surgical site infection (SSI) and periprosthetic joint infection (PJI) following total joint arthroplasty (TJA) remains a clinically significant and underexplored issue. The aim of this study is to investigate the association between operative time and the risk of subsequent SSI and PJI in patients undergoing primary TJA.

Methods

We retrospectively reviewed 17,342 primary unilateral total knee arthroplasty and total hip arthroplasty performed at a single institution between 2005 and 2016, with a minimum follow-up of 1 year. A multivariate logistic regression model was conducted to identify the association between operative time and the development of SSI within 90 days and PJI within 1 year.

Results

Overall, the incidence of 90-day SSI and 1-year PJI was 1.2% and 0.8%, respectively. Patients with an operative time of >90 minutes had a significantly higher incidence of SSI and PJI (2.1% and 1.4%, respectively) compared to cases lasting between 60 and 90 minutes (1.1% and 0.7%), and those lasting ≤60 minutes (0.9% and 0.7%, P < .01). In the multivariate model, the risk for infection increased by an odds ratio of 1.346 (95% confidential interval 1.114-1.627) for 90-day SSI and 1.253 (95% confidential interval 1.060-1.481) for 1-year PJI for each 20-minute increase in operative time.

Conclusion

In patients undergoing primary TJA, each 20-minute increase in operative time was associated with nearly a 25% increased risk of subsequent PJI. We advocate that surgeons pay close attention to this underappreciated risk factor while maintaining safe operative practices, which minimize unnecessary steps and wasted time in the operating room.  相似文献   
2.
Autosomal dominant transmission of isolated congenital vertical talus   总被引:1,自引:0,他引:1  
We report vertical transmission of isolated congenital vertical talus through three generations of a Honduran family. Five of nine affected family members were examined and the diagnosis was confirmed radiographically. There was incomplete penetrance in one clinically unaffected woman with two affected children. Bilateral and unilateral involvement was seen with a wide range of severity. Based on this family and on cases reviewed from the literature, we propose that isolated congenital vertical talus can be inherited as an autosomal dominant trait with variable expression and incomplete penetrance.  相似文献   
3.
4.
The effects of anesthesia on otoacoustic emissions   总被引:4,自引:0,他引:4  
We have measured transient-evoked and distortion-product otoacoustic emissions (OAEs) in the chinchilla and compared them in the awake and anesthetized animal (using either ketamine or barbiturate agents). We report a significant increase in OAE amplitudes during anesthesia, particularly using ketamine. These effects are most evident for transient-evoked otoacoustic emissions (TEOAEs) as measured in the non-linear mode. Our data support the hypothesis that tonic activity levels in cochlear efferents may be reduced by anesthetic effects, either directly or indirectly (e.g., by general reductions in descending pathway activity), and that reduced cochlear efferent activity will result in the observed increase of OAE amplitudes.  相似文献   
5.
Posttransplant CD30(+) (Ki-1) anaplastic large cell lymphoma (ALCL) is rare. A review of the literature revealed only 3 such cases. All 3 cases were developed after single-organ transplantation. We describe CD30(+) (Ki-1) ALCL in a dual-organ (liver and heart) transplantation recipient. The patient was a 68-year-old white female who underwent an orthotopic heart transplantation in 1999 and a liver transplantation in 2000. She presented with nausea and was found to have CD30(+) (Ki-1) ALCL by pathologic examination of the gastric antrum biopsy specimen. To our knowledge, this patient represents the first reported case of posttransplant CD30(+) ALCL following a dual-organ transplantation.  相似文献   
6.
INTRODUCTION: Researchers and clinicians have increasingly recognized that biological markers may help identify patients who are at risk for suicide. The objective of this retrospective, cross-sectional study was to compare the prevalence and location of white matter hyperintensities (WMH) in young inpatients with major depressive disorder (MDD) with and without histories of suicide attempts. METHODS: T2-weighted magnetic resonance images (MRI) of 102 young psychiatric inpatients with MDD were rated for the presence of WMH. Medical charts were reviewed to ascertain history of suicide attempt, demographic and clinical variables. Fisher's Exact Tests and logistic regression modeling were used to test the association between WMH and suicidality. RESULTS: Bivariate analysis showed that the prevalence of periventricular WMH was significantly higher in subjects with past suicide attempts (Fisher's Exact Test, p=0.02). Logistic regression analyses controlling for age, sex, and several clinical risk factors supported this finding (odds ratio=5.7; 95% confidence interval: 1.6, 21.2). LIMITATIONS: Due to the retrospective, cross-sectional design of our study, we are unable to determine if the WMH preceded or followed past suicide attempts. The generalizability of our findings is limited since this group of inpatients is more severely ill than the general psychiatric population. CONCLUSIONS: The increased prevalence of periventricular WMH in young adults with MDD and a history of suicide attempt, compared to similarly depressed adults without such a history, is consistent with our findings in children and youth, and suggests there might be neurobiological in addition to psychosocial risk factors for suicide.  相似文献   
7.
BACKGROUND: Congenital heart defects (CHDs) occur in approximately 1% of all live births. Although most CHDs are of unknown etiology, a family history of CHDs is a known risk factor, and offspring of individuals with CHDs are at a higher risk of having CHDs. The aim of this study was to investigate the relative risk for CHDs to offspring of individuals with CHDs. METHODS: The prevalence rates of CHDs in offspring of 203 individuals with CHDs and 282 individuals without CHDs were investigated. The study participants completed a questionnaire that included information on medical and reproductive history, lifestyle indicators, and family history of CHDs and other congenital malformations. The prevalence rates of CHDs in offspring were calculated. RESULTS: The prevalence of CHDs was 3.1% (18/575) in offspring of individuals with CHDs and 1.3% (8/589) in offspring of individuals without CHDs. The adjusted odds ratio for CHDs to offspring of parents with CHDs was 1.73 (95% confidence interval [95% CI] 0.89-2.44, p=0.02). The estimated relative risk for offspring to females with CHD was higher than for males [2.3 (95% CI 1.1-4.7, p=0.03) versus 1.31 (95% CI 0.48-4.30, p=0.66), respectively]. There was no suggestion of association between CHDs and maternal smoking, alcohol consumption, and use of medication during pregnancy. CONCLUSIONS: Offspring of parents with CHDs are at a higher risk for CHDs compared with the general population. Couples where one member is affected with CHD should receive pre-conceptional or pre-natal genetic counseling and should be informed about the magnitude of the potential risk of CHDs to the offspring.  相似文献   
8.
Clinical, radiographic and morphologic analysis of nineteen cases of perinatal (lethal) hypophosphatasia was performed. Three families each had two affected offspring. All of the patients had lethal short limb dwarfism with very soft calvaria. Other clinical findings included polyhydramnios, blue sclerae and spurs in the mid-portion of the forearms and lower legs. Considerable variability was found in the skeletal radiographs. In addition to the well known radiographic features such as generalized decrease in the size of ossified bones with some bones not ossified at all, other changes observed included: 1) marked variability in the amount of bone ossification; 2) variability between patients as to which bones were most severely affected; 3) unusually dense, round, flattened, butterfly shaped; and saggitally clefted vertebral bodies; 4) variability in femoral shape including chromosome like, campomelic like, and shortening with or without metaphyseal cupping or irregularities; 5) osteochondral projections (Bowdler spurs) of the midshaft of the fibula and ulna. Recognition of the marked clinical and radiographic variability in this autosomal recessive lethal skeletal dysplasia is important for accurate genetic counseling and prenatal diagnosis.  相似文献   
9.
10.

Background

The global rise in infectious disease has led the Center for Disease Control and Prevention and the World Health Organization to release new guidelines for the prevention of surgical site infection.

Methods

In this article, we summarize current recommendations based on level of evidence, review unresolved and unaddressed issues, and supplement them with new literature.

Results

Although the guidelines discuss major issues in reducing surgical site infection, many questions remain unanswered.

Conclusion

These guidelines will hopefully help in setting a standard of care based on best evidence available and focus investigators on areas where evidence is lacking.  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