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   40249篇
  免费   3163篇
  国内免费   95篇
耳鼻咽喉   571篇
儿科学   1655篇
妇产科学   1349篇
基础医学   5275篇
口腔科学   919篇
临床医学   4733篇
内科学   8686篇
皮肤病学   863篇
神经病学   3869篇
特种医学   1309篇
外国民族医学   3篇
外科学   4648篇
综合类   615篇
一般理论   70篇
预防医学   3601篇
眼科学   783篇
药学   2213篇
中国医学   17篇
肿瘤学   2328篇
  2021年   559篇
  2020年   406篇
  2019年   662篇
  2018年   730篇
  2017年   537篇
  2016年   605篇
  2015年   663篇
  2014年   933篇
  2013年   1481篇
  2012年   1906篇
  2011年   2115篇
  2010年   1120篇
  2009年   1020篇
  2008年   1916篇
  2007年   1911篇
  2006年   1900篇
  2005年   1855篇
  2004年   1869篇
  2003年   1709篇
  2002年   1729篇
  2001年   1149篇
  2000年   1204篇
  1999年   1042篇
  1998年   466篇
  1997年   397篇
  1996年   391篇
  1995年   357篇
  1994年   337篇
  1993年   349篇
  1992年   893篇
  1991年   823篇
  1990年   718篇
  1989年   749篇
  1988年   702篇
  1987年   724篇
  1986年   669篇
  1985年   697篇
  1984年   558篇
  1983年   483篇
  1982年   330篇
  1980年   271篇
  1979年   460篇
  1978年   309篇
  1977年   259篇
  1976年   283篇
  1975年   270篇
  1974年   299篇
  1973年   294篇
  1972年   267篇
  1971年   261篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.

Objective

To examine whether a healthy weight intervention embedded in the Parents as Teachers (PAT) home visiting program, which was previously found to improve mothers’ body mass index (BMI) and obesity-related behaviors, changed the BMI of preschool children or maternal feeding practices.

Methods

This stratified randomized trial included preschool-aged children at risk for overweight whose mothers were overweight or had obesity (n?=?179). The Healthy Eating and Active Living Taught at Home (HEALTH) intervention was based on the Diabetes Prevention Program. Differences were examined using repeated-measures mixed-ANOVA models.

Results

Compared with PAT usual care, the HEALTH intervention had no effect on children's BMI or maternal feeding practices. However, combined analyses showed that children's BMI percentile decreased (P??=?.007), BMI z-scores were maintained (P??=?.19), and 3 of 8 feeding practices improved over time (P < .05).

Conclusions and Implications

Additional research is needed to assess the effectiveness of PAT to prevent preschool-age obesity using rigorous designs (eg, group-randomized trials) and to identify its active components. HEALTH is ready to be scaled up to prevent maternal weight gain through embedding within the national PAT program.  相似文献   
3.
4.
5.
6.
7.

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   
8.

Introduction

Physician communication impacts patient outcomes. However, communication skills, especially around difficult conversations, remain suboptimal, and there is no clear way to determine the validity of entrustment decisions. The aims of this study were to 1) describe the development of a simulation-based mastery learning (SBML) curriculum for breaking bad news (BBN) conversation skills and 2) set a defensible minimum passing standard (MPS) to ensure uniform skill acquisition among learners.

Innovation

An SBML BBN curriculum was developed for fourth-year medical students. An assessment tool was created to evaluate the acquisition of skills involved in a BBN conversation. Pilot testing was completed to confirm improvement in skill acquisition and set the MPS.

Outcomes

A BBN assessment tool containing a 15-item checklist and six scaled items was developed. Students' checklist performance improved significantly at post-test compared to baseline (mean 65.33%, SD = 12.09% vs mean 88.67%, SD = 9.45%, P < 0.001). Students were also significantly more likely to have at least a score of 4 (on a five-point scale) for the six scaled questions at post-test. The MPS was set at 80%, requiring a score of 12 items on the checklist and at least 4 of 5 for each scaled item. Using the MPS, 30% of students would require additional training after post-testing.

Comments

We developed a SBML curriculum with a comprehensive assessment of BBN skills and a defensible competency standard. Future efforts will expand the mastery model to larger cohorts and assess the impact of rigorous education on patient care outcomes.  相似文献   
9.
10.
We present the case of 7‐year‐old African American girl with loose anagen syndrome. Although this is a common cause of hair loss in Caucasian children, and there have been reports of cases occurring in dark‐skinned children of North African and Middle Eastern descent, to our knowledge there have been no cases reported in black children of sub‐Saharan African ancestry. We present this case to broaden the differential diagnosis of hair loss in African Americans.  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