全文获取类型
收费全文 | 409958篇 |
免费 | 46463篇 |
国内免费 | 171篇 |
出版年
2018年 | 3535篇 |
2017年 | 3536篇 |
2016年 | 4739篇 |
2015年 | 6323篇 |
2014年 | 7360篇 |
2013年 | 11064篇 |
2012年 | 12323篇 |
2011年 | 12463篇 |
2010年 | 8321篇 |
2009年 | 7779篇 |
2008年 | 11325篇 |
2007年 | 11456篇 |
2006年 | 11089篇 |
2005年 | 10457篇 |
2004年 | 10384篇 |
2003年 | 10016篇 |
2002年 | 9786篇 |
2001年 | 19069篇 |
2000年 | 19248篇 |
1999年 | 15657篇 |
1998年 | 5484篇 |
1997年 | 5752篇 |
1996年 | 5539篇 |
1995年 | 5037篇 |
1994年 | 5166篇 |
1993年 | 5018篇 |
1992年 | 13009篇 |
1991年 | 12432篇 |
1990年 | 12361篇 |
1989年 | 12306篇 |
1988年 | 11210篇 |
1987年 | 10651篇 |
1986年 | 9903篇 |
1985年 | 9932篇 |
1984年 | 8073篇 |
1983年 | 7019篇 |
1982年 | 5329篇 |
1981年 | 4705篇 |
1980年 | 4577篇 |
1979年 | 7709篇 |
1978年 | 5964篇 |
1977年 | 5324篇 |
1976年 | 5141篇 |
1975年 | 5545篇 |
1974年 | 5803篇 |
1973年 | 5722篇 |
1972年 | 5175篇 |
1971年 | 4572篇 |
1970年 | 4045篇 |
1969年 | 3746篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
251.
252.
253.
254.
255.
Abstract— The effect of excess leucine in the diet on serotonin metabolism in the brain was investigated in experimental animals. It was found that:
(1) Animals receiving diets containing 3 % and 8 % leucine and those receiving jowar diets had significantly lower levels of serotonin in the brain.
(2) Intraperitoneal administration of the precursor amino acid 5-HTP increased the serotonin concentration in brain in both control and leucine-fed animals. However, the serotonin concentration in leucine-fed animals was significantly lower than that of pairfed controls. Larger amounts of the synthesized serotonin were found to be catabolized in 3 hr in leucine-fed animals than in control animals.
(3) The in vitro uptake of [14 C]5-HTP by brain slices of animals fed leucine was found to be similar to that of control animals.
(4) The basal concentration of 5-HIAA in brain was higher in leucine-fed animals, suggesting a higher rate of catabolism of serotonin.
(5) Administration of nicotinic acid resulted in a further fall of serotonin concentration in the brains of leucine-fed animals but not in control animals. 相似文献
(1) Animals receiving diets containing 3 % and 8 % leucine and those receiving jowar diets had significantly lower levels of serotonin in the brain.
(2) Intraperitoneal administration of the precursor amino acid 5-HTP increased the serotonin concentration in brain in both control and leucine-fed animals. However, the serotonin concentration in leucine-fed animals was significantly lower than that of pairfed controls. Larger amounts of the synthesized serotonin were found to be catabolized in 3 hr in leucine-fed animals than in control animals.
(3) The in vitro uptake of [
(4) The basal concentration of 5-HIAA in brain was higher in leucine-fed animals, suggesting a higher rate of catabolism of serotonin.
(5) Administration of nicotinic acid resulted in a further fall of serotonin concentration in the brains of leucine-fed animals but not in control animals. 相似文献
256.
257.
W P Hempfling 《Biochimica et biophysica acta》1970,205(2):169-182
258.
259.
260.