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   195714篇
  免费   13648篇
  国内免费   724篇
耳鼻咽喉   2658篇
儿科学   5506篇
妇产科学   3750篇
基础医学   25604篇
口腔科学   3885篇
临床医学   19323篇
内科学   41555篇
皮肤病学   3242篇
神经病学   19505篇
特种医学   6761篇
外国民族医学   24篇
外科学   28365篇
综合类   2595篇
现状与发展   3篇
一般理论   225篇
预防医学   15225篇
眼科学   5495篇
药学   12933篇
中国医学   214篇
肿瘤学   13218篇
  2023年   754篇
  2022年   1315篇
  2021年   3101篇
  2020年   1903篇
  2019年   3170篇
  2018年   3675篇
  2017年   2658篇
  2016年   3097篇
  2015年   3747篇
  2014年   5481篇
  2013年   8420篇
  2012年   12139篇
  2011年   13044篇
  2010年   7274篇
  2009年   6701篇
  2008年   12158篇
  2007年   12956篇
  2006年   12451篇
  2005年   12816篇
  2004年   12234篇
  2003年   11655篇
  2002年   11217篇
  2001年   2105篇
  2000年   1792篇
  1999年   2112篇
  1998年   2523篇
  1997年   2204篇
  1996年   1872篇
  1995年   1757篇
  1994年   1570篇
  1993年   1498篇
  1992年   1460篇
  1991年   1365篇
  1990年   1240篇
  1989年   1228篇
  1988年   1192篇
  1987年   1125篇
  1986年   1167篇
  1985年   1267篇
  1984年   1500篇
  1983年   1429篇
  1982年   1785篇
  1981年   1664篇
  1980年   1562篇
  1979年   1060篇
  1978年   1123篇
  1977年   954篇
  1976年   865篇
  1975年   727篇
  1974年   774篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.

Background/purpose

Computed tomography (CT) derived Haller Index (HI) remains the standard for quantifying severity in patient with pectus excavatum (PE). Optical scanning described in literature reports optimistic results and new indices that correlate with HI. This study assessed the feasibility of a handheld White Light Scanner (WLS) to obtain 3D measurements and indices of PE deformity.

Methods

From April 2015–April 2017, WLS scanning was conducted by orthotists during clinical visits. Included were children with PE up to 18?years. Analysis assessed correlation of a WLS-derived severity index, Hebal-Malas Index (HMI), with physician measured PE Depth (PED), and CT-derived HI.

Results

Of 195 participants, 185(94%) patients with PE were scanned and 127(69%) had complete WLS data. For 88 patients undergoing monitoring, HMI correlated with PED (r?=?0.42, p?=?0.004). For 39 patients with pre-operative CT, HMI demonstrated strong correlation with HI (r?=?0.87, p < 0.0001).

Conclusions

WLS demonstrated high feasibility of scanning PE. WLS-derived HMI best correlates with HI for patients with severe pectus deformity. Our current data is suggestive that WLS is best applied for severe deformities and yet to be established for milder deformities. Future yearly WLS will provide data on deformity progression and surgical therapy.

Level of Evidence

IV.

Type of Study

Diagnostic Study.  相似文献   
52.
53.
54.
55.
56.

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   
57.
Congenital heart disease is a rare but important finding in adults who experience sudden death. Examination of the congenitally malformed heart has historically been considered esoteric and best left to those with expertise. The Cardiac Risk in the Young cardiovascular pathology laboratory based at St George's University of London has now received over 6,000 cases. Of these, 21 congenitally malformed hearts were retained for research and educational purposes. Hearts were assessed using sequential segmental analysis, and causes of death were adjudicated based on thorough macroscopic examination and histology. Congenital malformations that were encountered included atrial septal defects, ventricular septal defects, tetralogy of Fallot, and transposition of the great arteries in both its regular and congenitally corrected variants. Findings also included hearts with mirror-imaged and isomeric atrial appendages. Direct causes of death included myocardial fibrosis, pulmonary hypertension, and hemorrhage. A small but notable proportion did not reveal a substrate for arrhythmia, raising the question of whether the terminal event was due to the congenital heart disease itself, or an underlying channelopathy. Here, we demonstrate the value of simple sequential segmental analysis in describing and categorizing the cases, with the concept of the “morphological method” serving to identify the distinguishing features of the cardiac components. Clin. Anat. 33:394–404, 2020. © 2019 Wiley Periodicals, Inc.  相似文献   
58.
59.
60.
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