全文获取类型
收费全文 | 416405篇 |
免费 | 53188篇 |
国内免费 | 196篇 |
专业分类
469789篇 |
出版年
2018年 | 3556篇 |
2016年 | 4627篇 |
2015年 | 6599篇 |
2014年 | 7616篇 |
2013年 | 11023篇 |
2012年 | 12232篇 |
2011年 | 12580篇 |
2010年 | 8450篇 |
2009年 | 7877篇 |
2008年 | 11105篇 |
2007年 | 11469篇 |
2006年 | 10663篇 |
2005年 | 10289篇 |
2004年 | 9934篇 |
2003年 | 9911篇 |
2002年 | 9529篇 |
2001年 | 19725篇 |
2000年 | 19935篇 |
1999年 | 15734篇 |
1998年 | 5477篇 |
1997年 | 6037篇 |
1996年 | 5741篇 |
1995年 | 5361篇 |
1994年 | 5255篇 |
1993年 | 5383篇 |
1992年 | 13354篇 |
1991年 | 13181篇 |
1990年 | 12564篇 |
1989年 | 12366篇 |
1988年 | 11279篇 |
1987年 | 10925篇 |
1986年 | 10209篇 |
1985年 | 10159篇 |
1984年 | 8502篇 |
1983年 | 7339篇 |
1982年 | 5642篇 |
1981年 | 5023篇 |
1980年 | 4845篇 |
1979年 | 7997篇 |
1978年 | 6397篇 |
1977年 | 5822篇 |
1976年 | 5488篇 |
1975年 | 6028篇 |
1974年 | 6220篇 |
1973年 | 6150篇 |
1972年 | 5551篇 |
1971年 | 5106篇 |
1970年 | 4258篇 |
1969年 | 4101篇 |
1968年 | 3674篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
971.
972.
973.
974.
975.
976.
977.
978.
979.
The metabolism of 2-deoxy-D-galactose has been studied in AS-30D rat ascites hepatoma cells in suspension. Using 2-deoxy-D-(1-14C)galactose and an alkaline ethanol deproteinization procedure, the quantitatively identified metabolites included 2-deoxy-D-galactose 1-phosphate comprising 99.3%, and UDP-2-deoxy-D-galactose and UDP-2-deoxy-D-glucose, together amounting to 0.4% of the total metabolites. After incubation for 5 h in the presence of 2-deoxy-D-galactose (1 mmo1/1), the content of 2-deoxy-D-galactose 1-phosphate reached 35 mmo1x(kg cells)-1. The rate of phosphorylation of 2-deoxy-D-galactose was rapid during the first 30 min and decreased to approximately 20% of this rate during the subsequent hours. The rapid trapping of Pi in the form of 2-deoxy-D-galactose 1-phosphate resulted in a depression of free intracellular Pi in spite of a concomitant increase in net 32Pi uptake from the medium and a decrease of ATP and other 5'-nucleotides. The rates of glucose utilization and lactate production were depressed by more than 80% in the presence of 2-deoxy-D-galactose (1 mmo1/1). Interruption of Pi trapping by removal of 2-deoxy-D-galactose from the medium reversed the depressions of Pi and ATP and resulted in a rapid but incomplete relief of glycolysis inhibition. Crossover analysis of glycolytic intermediates indicated an inhibition at the 6-phosphofructokinase step. The depression of glucose utilization may be mediated by the increased level of glucose 6-phosphate, a potent inhibitor of hexokinase. An additional inhibitory effect of a metabolite of 2-deoxy-D-galactose at the 6-phosphofructokinase step was indicated by crossover analysis after reversal of Pi and ATP depressions in the presence of a high intracellular content of 2-deoxy-D-glactose 1-phosphate. The quantitative analysis of the metabolites of 2-deoxy-D-galactose demonstrated the predominance of the monophosphate and the negligible formation of UPD derivatives of this sugar analog in AS-30D hepatoma cells. This provides a system for the investigation of a galactose analog as a phosphate-trapping agent in the virtual absence of uridylate trapping. 相似文献
980.