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   215297篇
  免费   15906篇
  国内免费   765篇
耳鼻咽喉   2303篇
儿科学   5645篇
妇产科学   4584篇
基础医学   27845篇
口腔科学   4652篇
临床医学   20391篇
内科学   46198篇
皮肤病学   2955篇
神经病学   20736篇
特种医学   7158篇
外国民族医学   13篇
外科学   33705篇
综合类   3428篇
现状与发展   2篇
一般理论   292篇
预防医学   19225篇
眼科学   4397篇
药学   14851篇
  1篇
中国医学   381篇
肿瘤学   13206篇
  2023年   779篇
  2022年   1214篇
  2021年   3518篇
  2020年   2176篇
  2019年   3493篇
  2018年   4079篇
  2017年   3295篇
  2016年   3505篇
  2015年   4156篇
  2014年   6234篇
  2013年   9010篇
  2012年   13432篇
  2011年   14550篇
  2010年   8231篇
  2009年   7463篇
  2008年   13862篇
  2007年   14694篇
  2006年   14167篇
  2005年   14630篇
  2004年   14077篇
  2003年   13113篇
  2002年   12652篇
  2001年   2060篇
  2000年   1704篇
  1999年   2248篇
  1998年   2894篇
  1997年   2489篇
  1996年   2282篇
  1995年   2014篇
  1994年   1799篇
  1993年   1703篇
  1992年   1357篇
  1991年   1306篇
  1990年   1188篇
  1989年   1072篇
  1988年   1121篇
  1987年   1105篇
  1986年   1078篇
  1985年   1163篇
  1984年   1542篇
  1983年   1523篇
  1982年   1840篇
  1981年   1669篇
  1980年   1571篇
  1979年   853篇
  1978年   983篇
  1977年   956篇
  1976年   857篇
  1975年   721篇
  1974年   696篇
排序方式: 共有10000条查询结果,搜索用时 359 毫秒
61.

Background

Most elderly trauma patients suffer blunt head injury and many utilize antithrombotic (AT) medications. The utility of delayed CT-head (D-CTH) in neurologically intact elderly patients using AT who have an intracranial hemorrhage (ICH) on presentation is unknown. We hypothesized that D-CTH would not alter clinical management and aimed to evaluate the role of D-CTH in this population.

Methods

A retrospective cohort study was performed. Patients ≥65 years sustaining blunt head injuries from January 2010 to July 2017 were identified using our level 1 trauma center database. AT-patients presenting with ICH who underwent D-CTH were included. Patients with worsened ICH were compared to those with stable to improved ICH on D-CTH. AT-patients were compared to a cohort of non-AT patients. Fisher’s Exact and Mann-Whitney U tests were utilized and a power analysis conducted.

Results

137?A?T and 34 non-AT patients were identified. There was no difference in hemorrhage progression or appearance of new ICH. No patient had a change in management from D-CTH in either cohort. AT-patients were slightly older (p?<?0.001), but cohorts were otherwise similar.50 AT-patients with worsened ICH were compared to 87 with stable ICH. There was no difference in cohort demographics. Hemorrhage progression did not vary with type of AT used but did increase if multiple types of synchronous ICH were present (p?<?0.001).

Conclusions

Our data supports abstaining from routine D-CTH of elderly ICH patients with an intact neurologic examination who are utilizing aspirin, clopidogrel or warfarin. Conclusions cannot be drawn regarding new oral anticoagulants (NOACs) given low enrollment. Further multicenter study is required to provide adequate power and detect small levels of management change.  相似文献   
62.
63.
64.
65.
66.
67.
68.
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   
69.
70.
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   
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