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   794565篇
  免费   82451篇
  国内免费   244篇
  2018年   7936篇
  2017年   7589篇
  2016年   10640篇
  2015年   13450篇
  2014年   16028篇
  2013年   23138篇
  2012年   25977篇
  2011年   26774篇
  2010年   18273篇
  2009年   16894篇
  2008年   23930篇
  2007年   24886篇
  2006年   23267篇
  2005年   22374篇
  2004年   22156篇
  2003年   21325篇
  2002年   20826篇
  2001年   34747篇
  2000年   34216篇
  1999年   27587篇
  1998年   10178篇
  1997年   10256篇
  1996年   9499篇
  1995年   9042篇
  1994年   8716篇
  1993年   8748篇
  1992年   22348篇
  1991年   21949篇
  1990年   21394篇
  1989年   20836篇
  1988年   19100篇
  1987年   18358篇
  1986年   17113篇
  1985年   16974篇
  1984年   13946篇
  1983年   12185篇
  1982年   9236篇
  1981年   8361篇
  1980年   7749篇
  1979年   12945篇
  1978年   10213篇
  1977年   9195篇
  1976年   8808篇
  1975年   9834篇
  1974年   10510篇
  1973年   10371篇
  1972年   9491篇
  1971年   8470篇
  1970年   7400篇
  1969年   7276篇
排序方式: 共有10000条查询结果,搜索用时 531 毫秒
71.
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   
72.
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   
73.
74.
75.
76.
77.
78.
79.
80.
The Saccharomyces cerevisiae SSU1 gene was isolated based on its ability to complement a mutation causing sensitivity to sulfite, a methionine intermediate. SSU1 encodes a deduced protein of 458 amino acids containing 9 or 10 membrane-spanning domains but has no significant similarity to other proteins in public databases. An Ssu1p-GEP fusion protein was localized to the plasma membrane. Multicopy suppression analysis, undertaken to explore relationships among genes previously implicated in sulfite metabolism, suggests a regulatory pathway in which SSU1 acts downstream of FZF1 and SSU3, which in turn act downstream of GRR1.  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