首页 | 官方网站   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   176754篇
  免费   11964篇
  国内免费   1266篇
医药卫生   189984篇
  2023年   828篇
  2022年   673篇
  2021年   4467篇
  2020年   2661篇
  2019年   3921篇
  2018年   4788篇
  2017年   3532篇
  2016年   4534篇
  2015年   6059篇
  2014年   7474篇
  2013年   9356篇
  2012年   13988篇
  2011年   13684篇
  2010年   8036篇
  2009年   6731篇
  2008年   10527篇
  2007年   10602篇
  2006年   9825篇
  2005年   9410篇
  2004年   8498篇
  2003年   7461篇
  2002年   6607篇
  2001年   4525篇
  2000年   4112篇
  1999年   3379篇
  1998年   1407篇
  1997年   1032篇
  1996年   998篇
  1995年   1004篇
  1994年   903篇
  1993年   772篇
  1992年   1651篇
  1991年   1671篇
  1990年   1434篇
  1989年   1307篇
  1988年   1214篇
  1987年   1102篇
  1986年   1072篇
  1985年   949篇
  1984年   736篇
  1983年   653篇
  1982年   505篇
  1981年   492篇
  1980年   438篇
  1979年   577篇
  1978年   460篇
  1977年   439篇
  1976年   387篇
  1974年   390篇
  1973年   361篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Numerous studies showed that postural balance improves through light touch on a stable surface highlighting the importance of haptic information, seemingly downplaying the mechanical contributions of the support. The present study examined the mechanical effects of canes for assisting balance in healthy individuals challenged by standing on a beam. Sixteen participants supported themselves with two canes, one in each hand, and applied minimal, preferred, or maximum force onto the canes. They positioned the canes in the frontal plane or in a tripod configuration. Statistical analysis used a linear mixed model to evaluate the effects on the center of pressure and the center of mass. The canes significantly reduced the variability of the center of pressure and the center of mass to the same level as when standing on the ground. Increasing the exerted force beyond the preferred level yielded no further benefits, although in the preferred force condition, participants exploited the altered mechanics by resting their arms on the canes. The tripod configuration allowed for larger variability of the center of pressure in the task-irrelevant anterior–posterior dimension. High forces had a destabilizing effect on the canes: the displacement of the hand on the cane handle increased with the force. Given this static instability, these results show that using canes can provide not only mechanical benefits but also challenges. From a control perspective, effort can be reduced by resting the arms on the canes and by channeling noise in the task-irrelevant dimensions. However, larger forces exerted onto the canes can also have destabilizing effects and the instability of the canes needs to be counteracted, possibly by arm and shoulder stiffness. Insights into the variety of mechanical effects is important for the design of canes and the instructions of how to use them.  相似文献   
2.
3.
4.
5.
Minimally invasive approaches are increasingly being applied in surgeries and have recently been used in living donor hepatectomy. We have developed a safe and reproducible method for minimally invasive living donor liver transplantation, which consists of pure laparoscopic explant hepatectomy and pure laparoscopic implantation of the graft, which was inserted through a suprapubic incision. Pure laparoscopic explant hepatectomy without liver fragmentation was performed in a 60-year-old man with alcoholic liver cirrhosis and hepatocellular carcinoma. The explanted liver was retrieved through a suprapubic incision. A modified right liver graft, procured from his 24-year-old son using the pure laparoscopic method, was inserted through a suprapubic incision, and implantation was performed intracorporeally throughout the procedure. The time required to remove the liver was 369 min, and the total operative time was 960 min. No complications occurred during or after the surgery. The patient recovered well, and his hospital stay was of 11 days. Pure laparoscopic living donor liver transplantation from explant hepatectomy to implantation was performed successfully. It is a feasible procedure when performed by a highly experienced surgeon and transplantation team. Further studies with larger sample sizes are needed to confirm its safety and feasibility.

  相似文献   

6.
7.
8.
Journal of Immigrant and Minority Health - Little attention has been paid to online health information seeking (OHIS) among immigrants residing in rural areas. This study examines the intensity of...  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-23

京公网安备 11010802026262号