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   999013篇
  免费   110809篇
  国内免费   772篇
  2018年   9244篇
  2017年   8645篇
  2016年   12515篇
  2015年   17136篇
  2014年   20161篇
  2013年   28444篇
  2012年   32008篇
  2011年   32420篇
  2010年   21950篇
  2009年   20167篇
  2008年   28673篇
  2007年   29316篇
  2006年   27909篇
  2005年   26806篇
  2004年   26557篇
  2003年   25586篇
  2002年   24715篇
  2001年   47481篇
  2000年   47869篇
  1999年   37884篇
  1998年   13114篇
  1997年   13641篇
  1996年   12817篇
  1995年   12002篇
  1994年   11686篇
  1993年   11600篇
  1992年   30751篇
  1991年   30082篇
  1990年   29323篇
  1989年   28560篇
  1988年   26608篇
  1987年   24868篇
  1986年   23052篇
  1985年   22933篇
  1984年   18825篇
  1983年   15967篇
  1982年   12020篇
  1981年   10718篇
  1980年   10130篇
  1979年   17193篇
  1978年   13412篇
  1977年   12156篇
  1976年   10978篇
  1975年   12288篇
  1974年   13096篇
  1973年   12972篇
  1972年   11565篇
  1971年   10616篇
  1970年   9151篇
  1969年   8840篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
The goal of this study was to develop a new implantable transducer for measuring anterior cruciate ligament (ACL) graft tension postoperatively in patients who have undergone ACL reconstructive surgery. A unique approach was taken of integrating the transducer into a femoral fixation device. To devise a practical in vivo calibration protocol for the fixation device transducer (FDT), several hypotheses were investigated: (1) The use of a cable versus the actual graft as the means for applying load to the FDT during calibration has no significant effect on the accuracy of the FDT tension measurements; (2) the number of flexion angles at which the device is calibrated has no significant effect on the accuracy of the FDT measurements; (3) the friction between the graft and femoral tunnel has no significant effect on measurement accuracy. To provide data for testing these hypotheses, the FDT was first calibrated with both a cable and a graft over the full range of flexion. Then graft tension was measured simultaneously with both the FDT on the femoral side and load cells, which were connected to the graft on the tibial side, as five cadaver knees were loaded externally. Measurements were made with both standard and overdrilled tunnels. The error in the FDT tension measurements was the difference between the graft tension measured by the FDT and the load cells. Results of the statistical analyses showed that neither the means of applying the calibration load, the number of flexion angles used for calibration, nor the tunnel size had a significant effect on the accuracy of the FDT. Thus a cable may be used instead of the graft to transmit loads to the FDT during calibration, thus simplifying the procedure. Accurate calibration requires data from just three flexion angles of 0, 45, and 90 deg and a curve fit to obtain a calibration curve over a continuous range of flexion within the limits of this angle group. Since friction did not adversely affect the measurement accuracy of the FDT, the femoral tunnel can be drilled to match the diameter of the graft and does not need to be overdrilled. Following these procedures, the error in measuring graft tension with the FDT averages less than 10 percent relative to a full-scale load of 257 N.  相似文献   
92.
Over the past 10 years the AIDS crisis has produced a large volume of writing. Much of this is documentary. Dozens of studies of AIDS from various clinical and political perspectives have been complemented by just as many published diaries, autobiographies, novels, plays, and poems. A few of these works have risen to the surface not only as extraordinarily valuable testimonies to the changes AIDS has wrought in individual and collective life but also as first-rate literary works, worth reading because beyond their immediate purposes they articulate with extraordinary lucidity and compassion some deep truths about the human--and the modern--condition. Paul Monette's Borrowed Time is among the most distinctive of those. It speaks not only for the community of people with AIDS and those who support them but for a generation.  相似文献   
93.
94.
95.
Trigger finger is a relatively common clinical entity, most frequently caused by stenosing tenosynovitis. Several other conditions not related to tenosynovitis also have been described as a cause of triggering, and these have been reviewed. We present a rare anomaly of the fourth lumbrical muscle insertion as a cause of triggering of the right little finger. This was completely relieved following excision of the anomalous muscle. This rare anatomic variant should be added to the list of potential causes of trigger finger.  相似文献   
96.
97.
98.
99.
100.
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