全文获取类型
收费全文 | 1997篇 |
免费 | 22篇 |
国内免费 | 5篇 |
专业分类
耳鼻咽喉 | 5篇 |
儿科学 | 136篇 |
妇产科学 | 26篇 |
基础医学 | 249篇 |
口腔科学 | 76篇 |
临床医学 | 115篇 |
内科学 | 281篇 |
皮肤病学 | 79篇 |
神经病学 | 192篇 |
特种医学 | 75篇 |
外科学 | 375篇 |
综合类 | 57篇 |
预防医学 | 67篇 |
眼科学 | 68篇 |
药学 | 88篇 |
中国医学 | 48篇 |
肿瘤学 | 87篇 |
出版年
2024年 | 2篇 |
2023年 | 2篇 |
2022年 | 7篇 |
2021年 | 36篇 |
2020年 | 6篇 |
2019年 | 374篇 |
2018年 | 295篇 |
2017年 | 126篇 |
2016年 | 9篇 |
2015年 | 14篇 |
2014年 | 34篇 |
2013年 | 13篇 |
2012年 | 25篇 |
2011年 | 32篇 |
2010年 | 30篇 |
2009年 | 13篇 |
2008年 | 11篇 |
2007年 | 12篇 |
2006年 | 13篇 |
2005年 | 16篇 |
2004年 | 10篇 |
2003年 | 6篇 |
2002年 | 10篇 |
2001年 | 7篇 |
2000年 | 9篇 |
1999年 | 10篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1996年 | 4篇 |
1995年 | 2篇 |
1994年 | 4篇 |
1993年 | 2篇 |
1992年 | 4篇 |
1991年 | 4篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1985年 | 111篇 |
1984年 | 165篇 |
1983年 | 100篇 |
1982年 | 123篇 |
1981年 | 117篇 |
1980年 | 78篇 |
1979年 | 65篇 |
1978年 | 64篇 |
1977年 | 31篇 |
1976年 | 12篇 |
1975年 | 2篇 |
1974年 | 2篇 |
1973年 | 3篇 |
排序方式: 共有2024条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
5.
Luke R.G. Pike Andrew Bang Brandon A. Mahal Allison Taylor Monica Krishnan Alexander Spektor Daniel N. Cagney Ayal A. Aizer Brian M. Alexander Osama Rahma Tracy Balboni Patrick A. Ott F. Stephen Hodi Jonathan D. Schoenfeld 《International journal of radiation oncology, biology, physics》2019,103(1):142-151
6.
7.
8.
9.
Shih-Chuan Chou Justine M. Nagurney Scott G. Weiner Arthur S. Hong J. Frank Wharam 《The American journal of emergency medicine》2019,37(6):1037-1043
ObjectivesTo describe recent trends in advanced imaging and hospitalization of emergency department (ED) syncope patients, both considered “low-value”, and examine trend changes before and after the publication of American College Emergency Physician (ACEP) syncope guidelines in 2007, compared to conditions that had no changes in guideline recommendations.MethodsWe analyzed 2002–2015 National Hospital Ambulatory Medical Care Survey data using an interrupted-time series with comparison series design. The primary outcomes were advanced imaging among ED visits with principal diagnosis of syncope and headache and hospitalization for ED visits with principal diagnosis of syncope, chest pain, dysrhythmia, and pneumonia. We adjusted annual imaging and hospitalization rates using survey-weighted multivariable logistic regression, controlling for demographic and visit characteristics. Using adjusted outcomes as datapoints, we compared linear trends and trend changes of annual imaging and hospitalization rates before and after 2007 with aggregate-level multivariable linear regression.ResultsFrom 2002 to 2007, advanced imaging rates for syncope increased from 27.2% to 42.1% but had no significant trend after 2007 (trend change: ?3.1%; 95%CI ?4.7, ?1.6). Hospitalization rates remained at approximately 37% from 2002 to 2007 but declined to 25.7% by 2015 (trend change: ?2.2%; 95%CI ?3.0, ?1.4). Similar trend changes occurred among control conditions versus syncope, including advanced imaging for headache (difference in trend change: ?0.6%; 95%CI ?2.8, 1.6) and hospitalizations for chest pain, dysrhythmia, and pneumonia (differences in trend changes: 0.1% [95%CI ?1.9, 2.0]; ?0.9% [95%CI ?3.1, 1.3]; and ?1.2% [95%CI ?5.3, 2.9], respectively).ConclusionsBefore and after the release of 2007 ACEP syncope guidelines, trends in advanced imaging and hospitalization for ED syncope visits had similar changes compared to control conditions. Changes in syncope care may, therefore, reflect broader practice shifts rather than a direct association with the 2007 ACEP guideline. Moreover, utilization of advanced imaging remains prevalent. To reduce low-value care, policymakers should augment society guidelines with additional policy changes such as reportable quality measures. 相似文献
10.