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   1335294篇
  免费   96047篇
  国内免费   2917篇
耳鼻咽喉   19722篇
儿科学   40240篇
妇产科学   38664篇
基础医学   187398篇
口腔科学   39842篇
临床医学   112664篇
内科学   262528篇
皮肤病学   30226篇
神经病学   106572篇
特种医学   53720篇
外国民族医学   435篇
外科学   208513篇
综合类   31040篇
现状与发展   6篇
一般理论   436篇
预防医学   91982篇
眼科学   31358篇
药学   100221篇
  3篇
中国医学   2989篇
肿瘤学   75699篇
  2018年   11760篇
  2015年   11906篇
  2014年   16720篇
  2013年   25299篇
  2012年   33093篇
  2011年   34952篇
  2010年   20786篇
  2009年   20263篇
  2008年   33643篇
  2007年   36770篇
  2006年   37326篇
  2005年   36092篇
  2004年   35176篇
  2003年   34146篇
  2002年   33687篇
  2001年   63657篇
  2000年   65388篇
  1999年   55438篇
  1998年   14679篇
  1997年   13486篇
  1996年   12948篇
  1995年   12240篇
  1994年   11487篇
  1992年   42805篇
  1991年   41327篇
  1990年   40588篇
  1989年   39587篇
  1988年   36990篇
  1987年   36440篇
  1986年   34928篇
  1985年   33116篇
  1984年   24849篇
  1983年   21075篇
  1982年   12678篇
  1981年   11569篇
  1980年   10777篇
  1979年   23930篇
  1978年   17072篇
  1977年   14841篇
  1976年   13393篇
  1975年   15272篇
  1974年   18087篇
  1973年   17566篇
  1972年   16813篇
  1971年   15723篇
  1970年   14923篇
  1969年   14355篇
  1968年   13466篇
  1967年   12023篇
  1966年   11266篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
103.

Background

Observational studies of the relative effectiveness of influenza vaccines are essential for public health decision making. Their estimates, however, are subject to bias due to unmeasured confounders. Instrumental variable (IV) methods can control for observed and unobserved confounders.

Methods

We used linked electronic medical record databases in the Veterans Health Administration (VHA) as well as Medicare administrative files to examine the relative vaccine effectiveness (rVE) of high-dose influenza vaccine (HD) versus standard-dose influenza vaccines (SD) in preventing hospitalizations among VHA-enrolled Veterans ≥65?years of age during 5 influenza seasons (2010–2011 through 2014–2015). Using multivariable IV Poisson regression modeling to address unmeasured confounding and bias, we analyzed the data by each season and through longitudinal analysis of all five seasons.

Findings

We included 3,638,924 person–influenza seasons of observation where 158,636 (4%) were among HD vaccine recipients and 3,480,288 (96%) were among SD vaccine recipients. Of the 1,728,562 Veterans, 1,702,824 (98.5%) were male and 1,299,412 (75%) were non-Hispanic white. Based on the longitudinal analysis of all five seasons, the IV-adjusted rVE estimate of HD vs. SD was 10% (95% CI, 8–12%) against all-cause hospitalization; 18% (95% CI, 15–21%) against cardiorespiratory-associated hospitalization; and 14% (95% CI, 6–22%) against influenza/pneumonia-associated hospitalization. The findings by season were similar.

Interpretation

Our analysis of VHA clinical data collected from approximately 1.7 million Veterans 65?years and older during five seasons demonstrates that high-dose influenza vaccine is more effective than standard-dose influenza vaccines in preventing influenza- or pneumonia-associated hospitalizations, cardiorespiratory hospitalizations, and all-cause hospitalizations.  相似文献   
104.
Choledochal cysts (CDCs) and biliary atresia (BA) are rare pediatric hepatobiliary anomalies that require surgical intervention due to increased risk of malignancy and liver failure, respectively. The underlying disease and operative procedures place patients at risk for long‐term complications, which may continue to affect them into adulthood. Lack of a transitional care model in the health‐care system potentiates the challenges they will face following aging out of their pediatric providers' care. We sought to elucidate the long‐term complications and challenges patients with CDCs and BA face, review the current literature regarding transitioning care, and propose guidelines aiding adult providers in continued care and surveillance of these patients. A literature review was performed to assess short‐term and long‐term complications after surgery and the current standards for transitioning care in patients with a history of CDCs and BA. While transitional programs exist for patients with other gastrointestinal diseases, there are few that focus on CDCs or BA. Generally, authors encourage medical record transmission from pediatric to adult providers, ensuring accuracy of information and compliance with treatment plans. Patients with CDCs are at risk for developing biliary malignancies, cholangitis, and anastomotic strictures after resection. Patients with BA develop progressive liver failure, necessitating transplantation. There are no consensus guidelines regarding timing of follow up for these patients. Based on the best available evidence, we propose a schema for long‐term surveillance.  相似文献   
105.
106.
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