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   956238篇
  免费   69670篇
  国内免费   1502篇
耳鼻咽喉   13235篇
儿科学   25237篇
妇产科学   23800篇
基础医学   135907篇
口腔科学   28781篇
临床医学   82999篇
内科学   188822篇
皮肤病学   19680篇
神经病学   74173篇
特种医学   37557篇
外国民族医学   79篇
外科学   155876篇
综合类   18703篇
现状与发展   1篇
一般理论   246篇
预防医学   63481篇
眼科学   22323篇
药学   74451篇
  4篇
中国医学   2277篇
肿瘤学   59778篇
  2018年   9669篇
  2017年   7519篇
  2016年   8336篇
  2015年   9512篇
  2014年   12881篇
  2013年   18528篇
  2012年   25732篇
  2011年   26776篇
  2010年   15831篇
  2009年   15138篇
  2008年   26132篇
  2007年   27150篇
  2006年   27834篇
  2005年   26739篇
  2004年   25845篇
  2003年   24741篇
  2002年   24187篇
  2001年   55537篇
  2000年   57257篇
  1999年   47579篇
  1998年   10977篇
  1997年   9653篇
  1996年   9753篇
  1995年   9087篇
  1994年   8430篇
  1993年   7730篇
  1992年   35881篇
  1991年   34263篇
  1990年   33051篇
  1989年   32172篇
  1988年   29257篇
  1987年   28506篇
  1986年   26536篇
  1985年   25382篇
  1984年   18005篇
  1983年   15304篇
  1982年   7902篇
  1981年   6858篇
  1979年   15905篇
  1978年   10662篇
  1977年   9134篇
  1976年   7927篇
  1975年   8678篇
  1974年   10531篇
  1973年   9914篇
  1972年   9403篇
  1971年   8897篇
  1970年   8449篇
  1969年   7956篇
  1968年   7218篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
The aim of this study was to analyse the effect of body mass index (BMI), both low and high values, on the perioperative complication rate in patients with oral squamous cell carcinoma (OSCC). The medical records of 259 patients operated between 2014 and 2017 for OSCC were reviewed. Univariate and multivariate analyses were performed. Sixty of the 259 patients developed 87 complications. Low or high BMI was not associated with the perioperative complication rate. A longer operating time and increased blood loss were associated with a higher perioperative complication rate and higher Clavien–Dindo grade. Low BMI, American Society of Anesthesiologists score 2 and 3, a longer operating time, and increased blood loss were associated with a longer hospital stay. Low BMI was associated with a longer hospital stay. Neither low nor high BMI was associated with the perioperative complication rate. A longer operating time and increased blood loss were associated with a higher perioperative complication rate and higher Clavien–Dindo grade.  相似文献   
82.
83.
84.
85.

Background

The purpose of the study was to evaluate the association between fetal echocardiographic measurements and the need for intervention (primary coarctation repair, staged coarctation repair, or catheter intervention) in prenatally diagnosed coarctation of the aorta.

Methods

A single-centre retrospective cohort study (2005-2015) of 107 fetuses diagnosed with suspected coarctation of the aorta in the setting of an apex-forming left ventricle and antegrade flow across the mitral and aortic valves.

Results

Median gestational age at diagnosis was 32 weeks (interquartile range, 23-35 weeks). Fifty-six (52%) did not require any neonatal intervention, 51 patients (48%) underwent a biventricular repair. In univariable analysis, an increase in ascending aorta (AAo) peak Doppler flow velocity (odds ratio [OR], 1.40 [95% confidence interval [CI], 1.05-1.91] per 20 cm/s; P = 0.03) was associated with intervention. No intervention was associated with larger isthmus size (OR, 0.23; P < 0.001), transverse arch diameter (OR, 0.23; P < 0.001), and aortic (OR, 0.72; P = 0.02), mitral (OR, 0.58; P = 0.001), and AAo (OR, 0.53; P < 0.001) z-scores. In multivariable analysis, higher peak AAo Doppler (OR, 2.51 [95% CI, 1.54-4.58] per 20 cm/s; P = 0.001) and younger gestational age at diagnosis (OR, 0.81 [95% CI, 0.70-0.93] per week; P = 0.005) were associated with intervention, whereas a higher AAo z-score (OR, 0.65 [95% CI, 0.43-0.94] per z; P = 0.029) and transverse arch dimension (OR, 0.44 [95% CI, 0.18-0.97]; P = 0.05) decreased the risk of intervention.

Conclusions

In prenatally suspected coarctation, the variables associated with intervention comprised smaller AAo and transverse arch size, earlier gestational age at diagnosis, and the additional finding of a higher peak AAo Doppler.  相似文献   
86.
87.

Background

Payers frequently rely on budget impact model (BIM) results to help determine drug coverage policy and its effect on their bottom line. It is unclear whether BIMs typically overestimate or underestimate real-world budget impact.

Objective

We examined how different modeling assumptions influenced the results of 6 BIMs from the Institute for Clinical and Economic Review (ICER).

Study Design

Retrospective analysis of pharmaceutical sales data.

Methods

From ICER reports issued before 2016, we collected estimates of 3 BIM outputs: aggregate therapy cost (ie, cost to treat the patient population with a particular therapy), therapy uptake, and price. We compared these against real-world estimates that we generated using drug sales data. We considered 2 classes of BIM estimates: those forecasting future uptake of new agents, which assumed “unmanaged uptake,” and those describing the contemporaneous market state (ie, estimates of current, managed uptake and budget impact for compounds already on the market).

Results

Differences between ICER's estimates and our own were largest for forecasted studies. Here, ICER's uptake estimates exceeded real-world estimates by factors ranging from 7.4 (sacubitril/valsartan) to 54 (hepatitis C treatments). The “unmanaged uptake” assumption (removed from ICER's approach in 2017) yields large deviations between BIM estimates and real-world consumption. Nevertheless, in some cases, ICER's BIMs that relied on current market estimates also deviated substantially from real-world sales data.

Conclusions

This study highlights challenges with forecasting budget impact. In particular, assumptions about uptake and data source selection can greatly influence the accuracy of results.  相似文献   
88.
We report a case of disseminated Trichosporon asahii in a patient on systemic antifungal therapy who presented with multiple cutaneous nodules suggestive of fungal infection. Histologic features resembled neutrophilic eccrine hidradenitis but staining with periodic acid‐Schiff and Gomori methenamine silver confirmed the clinical diagnosis. This case highlights the importance of maintaining suspicion for trichosporonosis and contextualizing histologic findings within the underlying clinical picture.  相似文献   
89.
90.
Shaving and other modes of epilation can cause undue anxiety, pain, or skin irritation in children. Here, we present hair trimming as a safe, painless, and cost‐effective alternative for patients with unwanted hair which may be performed indefinitely or until the child is old enough to direct management. In select cases, removing unwanted hair using this technique may facilitate dermatologic surveillance.  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