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   798791篇
  免费   83006篇
  国内免费   245篇
  2018年   7980篇
  2017年   7631篇
  2016年   10694篇
  2015年   13552篇
  2014年   16133篇
  2013年   23302篇
  2012年   26155篇
  2011年   26962篇
  2010年   18414篇
  2009年   16997篇
  2008年   24095篇
  2007年   25059篇
  2006年   23435篇
  2005年   22506篇
  2004年   22295篇
  2003年   21444篇
  2002年   20964篇
  2001年   34826篇
  2000年   34295篇
  1999年   27661篇
  1998年   10249篇
  1997年   10320篇
  1996年   9903篇
  1995年   9115篇
  1994年   8767篇
  1993年   8804篇
  1992年   22404篇
  1991年   22006篇
  1990年   21464篇
  1989年   20880篇
  1988年   19154篇
  1987年   18390篇
  1986年   17158篇
  1985年   17020篇
  1984年   14003篇
  1983年   12231篇
  1982年   9291篇
  1981年   8414篇
  1980年   7816篇
  1979年   13006篇
  1978年   10262篇
  1977年   9236篇
  1976年   8849篇
  1975年   9861篇
  1974年   10550篇
  1973年   10406篇
  1972年   9518篇
  1971年   8509篇
  1970年   7417篇
  1969年   7298篇
排序方式: 共有10000条查询结果,搜索用时 31 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