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   326761篇
  免费   23485篇
  国内免费   1239篇
耳鼻咽喉   3560篇
儿科学   9010篇
妇产科学   6356篇
基础医学   42793篇
口腔科学   6724篇
临床医学   31660篇
内科学   69136篇
皮肤病学   4216篇
神经病学   31692篇
特种医学   10593篇
外国民族医学   15篇
外科学   49503篇
综合类   4962篇
现状与发展   3篇
一般理论   441篇
预防医学   29327篇
眼科学   7553篇
药学   22817篇
  2篇
中国医学   639篇
肿瘤学   20483篇
  2023年   1291篇
  2022年   2008篇
  2021年   5730篇
  2020年   3494篇
  2019年   5718篇
  2018年   6685篇
  2017年   5179篇
  2016年   5748篇
  2015年   6699篇
  2014年   9898篇
  2013年   14219篇
  2012年   21126篇
  2011年   22906篇
  2010年   12791篇
  2009年   11734篇
  2008年   21240篇
  2007年   22470篇
  2006年   21569篇
  2005年   22000篇
  2004年   21015篇
  2003年   19519篇
  2002年   18842篇
  2001年   3077篇
  2000年   2363篇
  1999年   3258篇
  1998年   4203篇
  1997年   3592篇
  1996年   3082篇
  1995年   2846篇
  1994年   2518篇
  1993年   2409篇
  1992年   1874篇
  1991年   1745篇
  1990年   1595篇
  1989年   1464篇
  1988年   1508篇
  1987年   1495篇
  1986年   1400篇
  1985年   1578篇
  1984年   2027篇
  1983年   1952篇
  1982年   2467篇
  1981年   2212篇
  1980年   2049篇
  1979年   1183篇
  1978年   1291篇
  1977年   1257篇
  1976年   1113篇
  1975年   950篇
  1974年   939篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
A cluster randomized experiment was undertaken testing two sets of interventions encouraging enrollment in the Individually Paying Program (IPP), the voluntary component of the Philippines' social health insurance program. In early 2011, 1037 unenrolled IPP‐eligible families in 179 randomly selected intervention municipalities were given an information kit and offered a 50% premium subsidy valid until the end of 2011; 383 IPP‐eligible families in 64 control municipalities were not. In February 2012, the 787 families in the intervention sites who were still IPP‐eligible but had not enrolled had their vouchers extended, were resent the enrollment kits and received SMS reminders. Half the group also received a ‘handholding’ intervention: in the endline interview, the enumerator offered to help complete the enrollment form, deliver it to the insurer's office in the provincial capital, and mail the membership cards. The main intervention raised the enrollment rate by 3 percentage points (ppts) (p = 0.11), with an 8 ppt larger effect (p < 0.01) among city‐dwellers, consistent with travel time to the insurance office affecting enrollment. The handholding intervention raised enrollment by 29 ppts (p < 0.01), with a smaller effect (p < 0.01) among city‐dwellers, likely because of shorter travel times, and higher education levels facilitating unaided completion of the enrollment form. Copyright © The World Bank Health Economics © 2015 John Wiley & Sons, Ltd.  相似文献   
102.
103.
104.
105.
This article describes early stages in the acquisition of a first vocabulary by infants and young children. It distinguishes two major stages, the first of which operates by a stand‐alone word‐to‐world pairing procedure and the second of which, using the evidence so acquired, builds a domain‐specific syntax‐sensitive structure‐to‐world pairing procedure. As we show, the first stage of learning is slow, restricted in character, and to some extent errorful, whereas the second procedure is determinative, rapid, and essentially errorless. Our central claim here is that the early, referentially based learning procedure succeeds at all because it is reined in by attention‐focusing properties of word‐to‐world timing and related indicants of referential intent.  相似文献   
106.
107.
108.
109.
OBJECTIVE: A series of nasopharyngeal appliance designs is presented that represents our evolving experience over a 20-year period in the adjunctive use of prosthetic stents in the surgical correction of nasopharyngeal stenosis. DESIGN: Retrospective assessment of effectiveness of two nasopharyngeal stenosis hollow stent designs in a consecutive series of patients for relief of nasal obstructive symptoms. SETTING: Tertiary academic medical center, Craniofacial Program at Children's Hospital. PATIENTS: Four patients with nasopharyngeal stenosis were treated with a preoperatively fabricated stent made from a clasped palatal appliance onto which hollow acrylic conduits were extended through surgically re-created pharyngeal ports. A subsequent set of four patients with nasopharyngeal stenosis were treated with intraoperatively-fashioned silastic grommets, as opposed to palatal appliances. INTERVENTIONS: Postoperative intraoral stenting of nasopharyngeal ports. MAIN OUTCOME MEASURES: Maintenance of pharyngeal port opening after 1 year, improvement in nasal airway obstructive symptoms. RESULTS: The palatal appliance stents were less well tolerated and had a lower maintenance of port patency after device removal (4 of 8, 50%). The silastic grommets provided better retention into the ports and increased patient tolerance, as well as better 1-year port maintenance (6 of 8, 75%). CONCLUSIONS: The grommet stent appliance offers numerous advantages over a conventional dental-clasped appliance for prosthetic nasopharyngeal stenting, including obviation of extensive preoperative preparation, ease of insertion and removal, and exchange of air during the stenting period. Improved nasopharyngeal patency with this device may be due to greater patient tolerance and subsequent longer use.  相似文献   
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