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   775篇
  免费   41篇
  国内免费   15篇
耳鼻咽喉   5篇
儿科学   46篇
妇产科学   12篇
基础医学   76篇
口腔科学   9篇
临床医学   70篇
内科学   135篇
皮肤病学   5篇
神经病学   29篇
特种医学   172篇
外科学   137篇
综合类   46篇
预防医学   24篇
眼科学   1篇
药学   21篇
中国医学   2篇
肿瘤学   41篇
  2022年   5篇
  2021年   13篇
  2020年   9篇
  2019年   16篇
  2018年   19篇
  2017年   9篇
  2016年   9篇
  2015年   15篇
  2014年   16篇
  2013年   29篇
  2012年   26篇
  2011年   18篇
  2010年   18篇
  2009年   27篇
  2008年   9篇
  2007年   24篇
  2006年   21篇
  2005年   27篇
  2004年   16篇
  2003年   23篇
  2002年   15篇
  2001年   9篇
  2000年   14篇
  1999年   16篇
  1998年   28篇
  1997年   42篇
  1996年   47篇
  1995年   23篇
  1994年   27篇
  1993年   27篇
  1992年   10篇
  1991年   7篇
  1990年   12篇
  1989年   19篇
  1988年   25篇
  1987年   16篇
  1986年   23篇
  1985年   9篇
  1984年   5篇
  1983年   7篇
  1982年   14篇
  1981年   7篇
  1980年   8篇
  1978年   8篇
  1977年   7篇
  1976年   11篇
  1975年   6篇
  1969年   7篇
  1968年   8篇
  1966年   6篇
排序方式: 共有831条查询结果,搜索用时 0 毫秒
41.
42.
Color Doppler imaging (CDI) can demonstrate the relative direction and velocity of blood flow in color, superimposed on a conventional gray-scale ultrasound image that depicts stationary tissue. Twenty-five infants were studied with portable CDI in the coronal, sagittal, and axial planes. Bilateral antegrade flow was noted in the anterior, middle, and posterior cerebral arteries in all patients. Multiplanar CDI can image flow in the circle of Willis and its tributaries and branches.  相似文献   
43.
Klatskin tumors of the bile ducts: sonographic appearance   总被引:4,自引:0,他引:4  
Meyer  DG; Weinstein  BJ 《Radiology》1983,148(3):803-804
The authors present 3 cases of surgically proved Klatskin tumor diagnosed by ultrasound alone. Sonographic features of these tumors include (a) dilatation of the intrahepatic biliary ducts but not the extrahepatic duct, (b) non-union of the right and left hepatic ducts, and (c) small, solid masses at the hepatic hilus. Local spread to the liver may also be seen. If the pancreas appears normal and no primary tumor can be found, Klatskin tumor can be diagnosed with a high degree of accuracy.  相似文献   
44.
45.
46.
Knotting of intravascular catheters is an uncommon but a well‐recognized occurrence. The Swan–Ganz catheter (SGC) is the one that knots most commonly. A case of a knotted SGC is described in a patient with a persistent left‐sided superior vena cava, and we propose that the presence of a left‐sided superior vena cava is a risk factor for knot formation not previously reported. We review the published work on the risk factors for knot formation and on the techniques used to remove knotted SGC. We describe a technique using a gooseneck snare and Omni Flush catheter (Angiodynamics, Queensbury, NY, USA) to loosen and untie a knotted SGC.  相似文献   
47.
48.
Rugby union injuries to the cervical spine and spinal cord   总被引:1,自引:0,他引:1  
Injuries to the cervical spine are among the most serious injuries occurring as a result of participation in rugby. Outcomes of such injuries range from complete recovery to death, depending on the degree of spinal cord damage sustained. Much information has been gained regarding the mechanisms and frequency of such injuries, from case reports and case series studies. The most commonly reported mechanism of injury has been hyperflexion of the cervical spine, resulting in fracture dislocation of C4-C5 or C5-C6. Tracking both the trends of incidence of spinal injuries, and the effectiveness of injury prevention initiatives has proved difficult because of a lack of properly conducted epidemiological studies. Within the constraints of the research published to date, it appears that hookers and props have been at disproportionate risk of cervical spine injury, predominantly because of injuries sustained during scrummaging. While the scrum was the phase of play most commonly associated with spinal injuries throughout the 1980s in most rugby playing countries, there has been a trend through the 1990s of an increasing proportion of spinal injuries occurring in the tackle situation. The majority of injuries have occurred early in the season, when grounds tend to be harder, and players are lacking both practice and physical conditioning for the physical contact phases of the sport. A number of injury prevention measures have been launched, including changes to the laws of the game regarding scrummaging, and education programmes aimed at enforcing safe techniques and eliminating illegal play. Calls for case-registers and effective epidemiological studies have been made by researchers and physicians in most countries where rugby is widespread, but it appears to be only recently that definite steps have been made towards this goal. Well-designed epidemiological studies will be able to provide more accurate information about potential risk factors for injury such as age, grade, position, gender and ethnicity. Research into the long-term effects of participation in rugby on the integrity of the spinal column is warranted.  相似文献   
49.
Careful study of the pathophysiology and epidemiology of sports-related spine injuries brings to light many common features. The incidence increases as the sport becomes increasingly violent and aggressive. Poor conditioning and lack of knowledge of the proper techniques of the sport put the athlete at significant risk for head and spine injury. Improper helmet fit and the use of the head as an offensive weapon also are common features of injury. Although recognition of these features has resulted in a dramatic reduction in catastrophic neurological injury, the athlete remains at risk for less severe head and spine injury, and concussion remains at epidemic proportions at high school, university, and professional levels. It is hoped that careful recognition of the signs of concussion and knowledge of return-to-play criteria will prevent catastrophic complications from minor head injuries, although the long-term effects of multiple concussions on cognition may be problematic.  相似文献   
50.
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