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   1100431篇
  免费   118846篇
  国内免费   512篇
  1219789篇
  2018年   10466篇
  2017年   9862篇
  2016年   14254篇
  2015年   18920篇
  2014年   22093篇
  2013年   31926篇
  2012年   35967篇
  2011年   36758篇
  2010年   24979篇
  2009年   23082篇
  2008年   32646篇
  2007年   33947篇
  2006年   31495篇
  2005年   30511篇
  2004年   30264篇
  2003年   28926篇
  2002年   28078篇
  2001年   47240篇
  2000年   46952篇
  1999年   37777篇
  1998年   14258篇
  1997年   14420篇
  1996年   13812篇
  1995年   12648篇
  1994年   12521篇
  1993年   12449篇
  1992年   30967篇
  1991年   30126篇
  1990年   29478篇
  1989年   28941篇
  1988年   26387篇
  1987年   25368篇
  1986年   23601篇
  1985年   23445篇
  1984年   19592篇
  1983年   17009篇
  1982年   13119篇
  1981年   11910篇
  1980年   11043篇
  1979年   18437篇
  1978年   14516篇
  1977年   13207篇
  1976年   12543篇
  1975年   13738篇
  1974年   14833篇
  1973年   14593篇
  1972年   13369篇
  1971年   12043篇
  1970年   10373篇
  1969年   10095篇
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
81.
82.
Argon laser surgery is an effective treatment for ectasias and congenital port-wine stains; however, its use in children under the age of 13 is controversial. This paper reviews 202 children under the age of 13 who underwent argon laser treatments for congenital port-wine stains, spider angiomas, epidermal nevi, and lentigines. The clinical characteristics of port-wine stains in 170 children are discussed. Good to excellent results (moderate to complete clearing) in port-wine stains were obtained in 60 percent of patients and seemed to correlate best with lack of blanchability on pressure. Hypertrophic scarring was seen in only 7 children, all of whom had undressed wounds; no significant scarring has been seen in any subsequent child who had maintained a dressed wound postoperatively.  相似文献   
83.
Reconstruction of bony structures of the face is always a problem as big as the defect and the function that must be replaced. Everything from simple grafts to sophisticated distant bone flaps has been used. Based on the studies of Cutting et al., Psillakis et al., and Casanova et al., we have developed the full-thickness galeoparietal bone flap, initially for mandibular reconstruction, but of great use for all maxillofacial reconstructions. From July of 1987 to December of 1988, 14 patients have been operated on. The experience with this flap is shown in four patients as follows: primary reconstruction of a mandible as a result of ameloblastoma, secondary reconstruction of a mandible with associated old fractures and malalignment of segments, bilateral malar reconstruction in a patient with Treacher Collins syndrome, and severe sequelae of an already treated Romberg case. Small variations could be made to best accommodate the technique used to the defect we were treating. Some technical details, the experience, the results, and possible sequelae or complications are also discussed.  相似文献   
84.
85.
86.
87.
88.
89.
90.
Isopropanol administered in a large (6 g/kg, orally) as well as in a lower dose (1 g/kg, I.P.) is slowly oxidized into acetone by the intact rat. Using two inhibitors, 3 amino-1,2,4-triazole and pyrazole, investigations on the hepatic enzymatic system involved in the oxidation of isopropanol show that catalase does not play an important part in this pathway, contrary to alcohol dehydrogenase which is the major enzyme responsible for this oxidation. Although isopropanol oxidation is mainly catalysed in the liver through alcohol dehydrogenase, no alteration of the hepatic extramitochondrial redox state occurs after the administration of a large as well as of a lower dose of isopropanol. From these experiments it may be concluded that alterations of the liver NAD+/NADH ratio, which seem to play an important part in the ethanol induced fatty liver, are not involved in the isopropanol induced one.  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