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   398113篇
  免费   45652篇
  国内免费   361篇
  444126篇
  2016年   3679篇
  2015年   5526篇
  2014年   6424篇
  2013年   9203篇
  2012年   10268篇
  2011年   10336篇
  2010年   6831篇
  2009年   6444篇
  2008年   9146篇
  2007年   9626篇
  2006年   9138篇
  2005年   8896篇
  2004年   8794篇
  2003年   8379篇
  2002年   8365篇
  2001年   18228篇
  2000年   18775篇
  1999年   14931篇
  1998年   4935篇
  1997年   5204篇
  1996年   4841篇
  1995年   4634篇
  1994年   4571篇
  1993年   4566篇
  1992年   12072篇
  1991年   11657篇
  1990年   11313篇
  1989年   10967篇
  1988年   10353篇
  1987年   9873篇
  1986年   9379篇
  1985年   9462篇
  1984年   7820篇
  1983年   6725篇
  1982年   5352篇
  1981年   4984篇
  1980年   4522篇
  1979年   7626篇
  1978年   6159篇
  1977年   5656篇
  1976年   5340篇
  1975年   5998篇
  1974年   6626篇
  1973年   6570篇
  1972年   6087篇
  1971年   5510篇
  1970年   4757篇
  1969年   4718篇
  1968年   4300篇
  1967年   3616篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
901.
902.
903.
904.
Hyperthermic treatment at 43 degrees C suppressed the growth of Ehrlich ascites tumor (EAT) cells in vitro. Incubation of EAT cells at 43 degrees C for as little as 1.5 h totally abolished the transplantability of the tumor. At the same time, the rate of cellular glucose uptake, the density of glucose transporter on the cells as well as the extent of thymidine, uridine and leucine incorporation were significantly reduced.  相似文献   
905.
Preparations representing populations of (a) basal and spinous cells, (b) granular cells, and (c) stratum corneum cells were obtained by successive treatments of epidermal slices from pig skin with dilute buffered trypsin solutions. Total lipids accounted for about 8% of the cell dry weight in each of the three populations. Phospholipids, which predominated in the basal and spinous cells, accounted for only 21% of the total lipids in the granular cells and less than 0.1% in the stratum corneum. The latter cells contained more cholesterol (23% of total lipid) than either the granular cells (18%) or the basal and spinous cells (8%). The proportion of ceramide was also much higher in the stratum corneum (17%) and granular cells (9%) than in the basal and spinous cells (1%). The relative amounts of glycosphingolipid (glucosylceramide) and cholesteryl sulfate in the total lipids of stratum corneum cells were less than half those in the granular cells and basal and spinous cells. A novel phospholipid was a major component (26% of total) of the phospholipids from granular cells. The compound, which was partially characterized, contained phosphorus, fatty acids, and glycerol (molar ratio 1:3:2) and appeared to be a neutral derivative of phosphatidic acid.  相似文献   
906.
907.
908.
The fidelity of the regenerative response in the adult newt, Notophthalmus viridescens, was examined following repeated amputations at the level of the distal one-third of humerus. Three to four months following amputation, all regenerates were scored for gross morphology, reamputated, and stained with methylene blue for skeletal elements. The occurrence of abnormal regeneration with respect both to gross morphology and to skeletal structure was found to increase directly with the number of times the limb stumps were required to initiate dedifferentiation and repair. The initial amputation-regeneration process produced structurally normal replacement limbs in 91% of the cases examined. Reamputations of 4-digit regenerates (3--4 months after the previous transection) resulted in structurally abnormal regenerates in 28% of the cases following two amputations; 50% of the cases following three amputations; 65% of the cases following four amputations; and 81% of the cases following five amputations. The relationships between repeated dedifferentiation, proliferation, and redifferentiation and normal limb development are discussed.  相似文献   
909.
910.
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