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   1204篇
  免费   98篇
  国内免费   1篇
  2021年   16篇
  2020年   12篇
  2019年   10篇
  2018年   9篇
  2017年   16篇
  2016年   27篇
  2015年   39篇
  2014年   41篇
  2013年   56篇
  2012年   75篇
  2011年   52篇
  2010年   57篇
  2009年   33篇
  2008年   50篇
  2007年   41篇
  2006年   52篇
  2005年   42篇
  2004年   43篇
  2003年   36篇
  2002年   37篇
  2001年   38篇
  2000年   44篇
  1999年   31篇
  1998年   17篇
  1997年   16篇
  1996年   16篇
  1995年   9篇
  1994年   17篇
  1993年   16篇
  1992年   25篇
  1991年   19篇
  1990年   18篇
  1989年   22篇
  1988年   21篇
  1987年   17篇
  1986年   17篇
  1985年   16篇
  1984年   19篇
  1983年   10篇
  1982年   15篇
  1981年   11篇
  1980年   12篇
  1979年   20篇
  1978年   17篇
  1976年   12篇
  1975年   11篇
  1974年   9篇
  1973年   8篇
  1972年   8篇
  1970年   8篇
排序方式: 共有1303条查询结果,搜索用时 15 毫秒
31.
The xylanase gene from Cryptococcus albidus contains seven introns. Genomic and cDNA clones under the control of the CaMV 35S promoter were transferred into tobacco plants using Agrobacterium-mediated cell transformation. The genes were transcribed and the mRNAs were amplified by the polymerase chain reaction using primers on each side of the intron region. About 90% of the amplification products from plants transformed with the genomic clone corresponded to the size of the pre-mRNA (1.2 kb) and 10% represented the spliced product (0.85 kb). The 0.85 kb fragment was cloned and sequenced and the result indicated that the introns from the xylanase gene were accurately spliced by the plant cells.  相似文献   
32.
33.
Radioimmunoassays of platelet prostaglandins E1 and F1 alpha in platelet rich plasma or platelet suspension, demonstrate that both PGE1 and PGF1 alpha are present at higher concentrations than prostaglandins E2 and F2 alpha. Gas chromatography--mass spectrometry determinations of prostaglandins E1 and E2 in resting washed platelets confirm this difference. Lastly, there is a greater incorporation of [1--14C] acetate into prostaglandins E1 and F1 alpha compared to that into prostaglandins E2 and F2 alpha.  相似文献   
34.
Radioimmunoassays of platelet prostaglandins E1 and F in platelet rich plasma or platelet suspension, demonstrate that both PGE1 and PGF are present at higher concentrations than prostaglandins E2 and F. Gas chromatography — mass spectrometry determinations of prostaglandins E1 and E2 in resting washed platelets confirm this difference. Lastly, there is a greater incorporation of [1-14C] acetate into prostaglandins E1 and F compared to that into prostaglandins E2 and F.  相似文献   
35.
36.
The chemical communication of the epigean Necturus maculosus and the cave-living Proteus anguinus are compared in laboratory conditions. In both species a specks-specific substance transferred by water could be shown, another was deposited on the substrate.  相似文献   
37.
G. Daculsi  B.H. Fellah  T. Miramond  M. Durand 《IRBM》2013,34(4-5):346-348
Resorbable synthetic bone graft materials are mainly calcium phosphates. These materials differ in chemical composition and physical properties, particularly in regards of osteoconduction, osteogenic and/or osteoinductive properties. Several scaffolds are characterized and compared. Results from preclinical and clinical studies are selected. Osteoconductive properties have been largely described but “osteoinductive” properties have been less explored and documented. The purpose of this paper will be to present series of data demonstrating the differences in scaffolds for bone regeneration and to explain how dissolution and, biological precipitation into the micropores occur simultaneously with osteoid and bone formation after implantation in bony and non-bony sites and support the osteogenic/osteoinductive properties.  相似文献   
38.
The non-histone chromosomal proteins from mouse myeloma cell line X 63-Ag 8.653 have been studied using two dimensional polyacrylamide gel electrophoresis. Our results were compared to previous analysis of other myeloma cell lines.  相似文献   
39.
CELL CYCLE KINETICS IN AN IN VITRO TUMOR MODEL   总被引:1,自引:0,他引:1  
Cell cycle kinetic parameters of multicell spheroids in vitro have been estimated using thymidine labeling techniques and autoradiography. Both the mitotic index and thymidine labeling index decreased in larger spheroids, whereas the duration of the cell cycle, as determined by two independent methods utilizing labeled mitoses or labeled cells, was essentially independent of spheroid size or age. These results suggest that the tumor-like growth exhibited by spheroids is the result of a decreasing growth fraction and a large apparent cell loss, rather than a general elongation of the cell cycle.  相似文献   
40.
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