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   685899篇
  免费   77460篇
  国内免费   296篇
  763655篇
  2018年   6096篇
  2016年   8296篇
  2015年   11074篇
  2014年   13123篇
  2013年   18505篇
  2012年   20737篇
  2011年   21253篇
  2010年   14462篇
  2009年   13309篇
  2008年   19197篇
  2007年   19938篇
  2006年   18667篇
  2005年   17988篇
  2004年   18054篇
  2003年   17224篇
  2002年   16912篇
  2001年   28416篇
  2000年   28470篇
  1999年   22864篇
  1998年   8365篇
  1997年   8616篇
  1996年   8079篇
  1995年   7753篇
  1994年   7609篇
  1993年   7567篇
  1992年   19426篇
  1991年   18994篇
  1990年   18604篇
  1989年   18030篇
  1988年   17157篇
  1987年   16465篇
  1986年   15102篇
  1985年   15148篇
  1984年   12652篇
  1983年   11035篇
  1982年   8605篇
  1981年   7723篇
  1980年   7396篇
  1979年   12445篇
  1978年   9600篇
  1977年   8966篇
  1976年   8533篇
  1975年   9195篇
  1974年   10201篇
  1973年   10162篇
  1972年   9437篇
  1971年   8656篇
  1970年   7551篇
  1969年   7376篇
  1968年   6882篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
51.
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   
52.
53.
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   
54.
55.
56.
57.
58.
59.
60.
An agar-degrading marine bacterium identified as a Microscilla species was isolated from coastal California marine sediment. This organism harbored a single 101-kb circular DNA plasmid designated pSD15. The complete nucleotide sequence of pSD15 was obtained, and sequence analysis indicated a number of genes putatively encoding a variety of enzymes involved in polysaccharide utilization. The most striking feature was the occurrence of five putative agarase genes. Loss of the plasmid, which occurred at a surprisingly high frequency, was associated with loss of agarase activity, supporting the sequence analysis results.  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