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   794136篇
  免费   82504篇
  国内免费   244篇
  2018年   7934篇
  2017年   7583篇
  2016年   10641篇
  2015年   13457篇
  2014年   16031篇
  2013年   23131篇
  2012年   25979篇
  2011年   26761篇
  2010年   18276篇
  2009年   16891篇
  2008年   23925篇
  2007年   24897篇
  2006年   23262篇
  2005年   22381篇
  2004年   22148篇
  2003年   21306篇
  2002年   20828篇
  2001年   34749篇
  2000年   34206篇
  1999年   27582篇
  1998年   10184篇
  1997年   10260篇
  1996年   9504篇
  1995年   9044篇
  1994年   8720篇
  1993年   8754篇
  1992年   22336篇
  1991年   21923篇
  1990年   21361篇
  1989年   20812篇
  1988年   19088篇
  1987年   18326篇
  1986年   17090篇
  1985年   16951篇
  1984年   13936篇
  1983年   12173篇
  1982年   9238篇
  1981年   8359篇
  1980年   7750篇
  1979年   12940篇
  1978年   10199篇
  1977年   9191篇
  1976年   8801篇
  1975年   9818篇
  1974年   10486篇
  1973年   10351篇
  1972年   9474篇
  1971年   8455篇
  1970年   7381篇
  1969年   7255篇
排序方式: 共有10000条查询结果,搜索用时 250 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