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   7181篇
  免费   472篇
  国内免费   12篇
耳鼻咽喉   53篇
儿科学   206篇
妇产科学   198篇
基础医学   773篇
口腔科学   82篇
临床医学   1336篇
内科学   1148篇
皮肤病学   76篇
神经病学   711篇
特种医学   144篇
外科学   763篇
综合类   134篇
一般理论   9篇
预防医学   912篇
眼科学   257篇
药学   372篇
中国医学   10篇
肿瘤学   481篇
  2023年   46篇
  2022年   68篇
  2021年   185篇
  2020年   88篇
  2019年   167篇
  2018年   186篇
  2017年   128篇
  2016年   135篇
  2015年   144篇
  2014年   211篇
  2013年   335篇
  2012年   440篇
  2011年   478篇
  2010年   289篇
  2009年   247篇
  2008年   443篇
  2007年   428篇
  2006年   377篇
  2005年   419篇
  2004年   409篇
  2003年   346篇
  2002年   353篇
  2001年   88篇
  2000年   93篇
  1999年   111篇
  1998年   66篇
  1997年   66篇
  1996年   51篇
  1995年   51篇
  1994年   34篇
  1993年   49篇
  1992年   57篇
  1991年   67篇
  1990年   57篇
  1989年   53篇
  1988年   41篇
  1987年   40篇
  1986年   39篇
  1985年   32篇
  1984年   55篇
  1983年   70篇
  1982年   62篇
  1981年   63篇
  1980年   75篇
  1979年   43篇
  1978年   44篇
  1977年   42篇
  1976年   27篇
  1974年   33篇
  1966年   26篇
排序方式: 共有7665条查询结果,搜索用时 468 毫秒
1.
2.
Ligation of a hemodynamically significant ductus arteriosus results in significant changes in loading conditions which have predictable consequences. Postligation cardiac syndrome, defined as hypotension requiring inotropic support and failure of oxygenation and ventilation, may occur 6‐12 hours following ligation due to left ventricular systolic and diastolic failure, respectively. Afterload is the primary driver of this decompensation. In this review, we describe the pathophysiological changes in loading conditions associated with postligation cardiac syndrome and other contributors to cardiovascular dysfunction following ductal ligation. We present strategies for perioperative optimization and a physiology‐based algorithm for postoperative management guided by targeted neonatal echocardiography. The use of these strategies to reduce the frequency of postligation deterioration may be an avenue to improve outcomes for neonates in this vulnerable patient population.  相似文献   
3.
The 2008 dioxin crisis occurred as a result of contamination of Irish pork. The event had significant implications for Ireland’s economy and the reputation of its agricultural industry, as well as raising concerns for human health. This study describes the results of a content analysis of Irish and UK newspaper coverage of the 2008 Irish dioxin crisis, as this is likely to provide insight into how public perceptions of this issue were shaped. Articles from 16 print publications were systematically sampled for the period December 2008 to February 2009. The resulting data set of 141 articles was examined using a coding protocol developed based on previous research and refined during piloting. Results indicated that the dioxin crisis was primarily portrayed by the media as an industry/economic crisis, dominant in 26.9% of articles in the sample. Within this dominant portrayal, the agricultural industry was frequently cited as being in crisis (42.6%); however, the implications of the crisis on the wider economic environment also received attention (17.7%). Differences between Irish and UK-based media were also examined, revealing that while the Irish media most frequently described the crisis in terms of its impact on the industry and economy, the UK media were more likely to portray the crisis as a risk to health. These dominant media messages and message framings have implications for the public understanding of the issue in each country and potential consequences regarding perception of the adequacy of existing food policy and regulatory oversight.  相似文献   
4.
5.
6.
7.
OBJECTIVE: To illustrate the safety and efficacy of the endoscopic laser approach for cricopharyngeal myotomy (CPM) compared to the traditional transcervical approach. STUDY DESIGN AND SETTING: Retrospective chart review of 22 patients undergoing CPM from 1996 to 2003 at the Mayo Clinic, Jacksonville. RESULTS: The laser CPM technique was used in 14 patients, and an open approach in 8. The mean hospital stay and operative times were shorter for the laser group. Functional outcome analyses showed improvement in both groups. There were no major complications in the laser group, while 1 patient in the transcervical group had a pharyngocutaneous fistula. CONCLUSIONS: The laser technique is at least as effective as the transcervical approach for CPM to improve dysphagia symptoms in the properly selected patient, with a low risk of major complications. SIGNIFICANCE: In this report, we provide the reader with data to support the safety and efficacy of laser CPM. EBM rating: B-3b.  相似文献   
8.
During the sixties many studies of creativity focussed upon the evaluation of outcomes or products and gave little serious attention to the study of the genesis and development of the cognitive abilities responsible for the products. As a result, creativity assessment was delayed until the child had developed the verbal and other expressive abilities necessary for product-orientated assessment and creativity was deprived of an adequate developmental theory.

This paper offers an explanation of creativity within a developmental constructivist framework. The focus is upon the nature of creative activity and not upon the evaluation of products. There is an attempt to demonstrate that creative activity may be observed from early infancy and that this early transformational activity increases in structural and contextual complexity as the individual develops.  相似文献   
9.
10.
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