全文获取类型
收费全文 | 783811篇 |
免费 | 95396篇 |
国内免费 | 424篇 |
出版年
2016年 | 8587篇 |
2015年 | 13054篇 |
2014年 | 15046篇 |
2013年 | 20922篇 |
2012年 | 23912篇 |
2011年 | 23859篇 |
2010年 | 16166篇 |
2009年 | 15343篇 |
2008年 | 21931篇 |
2007年 | 22495篇 |
2006年 | 21005篇 |
2005年 | 20267篇 |
2004年 | 20097篇 |
2003年 | 19444篇 |
2002年 | 18866篇 |
2001年 | 34360篇 |
2000年 | 34784篇 |
1999年 | 28059篇 |
1998年 | 10774篇 |
1997年 | 11408篇 |
1996年 | 10953篇 |
1995年 | 10359篇 |
1994年 | 10207篇 |
1993年 | 10034篇 |
1992年 | 23639篇 |
1991年 | 22902篇 |
1990年 | 22516篇 |
1989年 | 21859篇 |
1988年 | 20139篇 |
1987年 | 19776篇 |
1986年 | 18149篇 |
1985年 | 18226篇 |
1984年 | 15160篇 |
1983年 | 13231篇 |
1982年 | 10574篇 |
1981年 | 9428篇 |
1980年 | 8991篇 |
1979年 | 14588篇 |
1978年 | 11724篇 |
1977年 | 10587篇 |
1976年 | 9997篇 |
1975年 | 10823篇 |
1974年 | 11652篇 |
1973年 | 11447篇 |
1972年 | 10245篇 |
1971年 | 9494篇 |
1970年 | 8134篇 |
1969年 | 7687篇 |
1968年 | 6850篇 |
1967年 | 6182篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
261.
R M Arahuetes J López M Ramos 《Comparative biochemistry and physiology. B, Comparative biochemistry》1986,83(1):231-233
Glucose and ketone bodies production has been studied in hepatocytes isolated from fetuses at term of fed and fasted adrenalectomized mothers. Maternal adrenalectomy diminishes the fetal liver weight. This effect is increased when the adrenalectomized pregnant rat is fasted for the last 2 days of gestation. Maternal adrenalectomy diminishes glucose production in hepatocytes isolated from fetuses at term. This diminution is markedly greater when the adrenalectomized pregnant rat is fasted for the last 48 hr of gestation. Maternal adrenalectomy diminishes ketone bodies production in hepatocytes isolated from fetuses at term. 相似文献
262.
263.
264.
265.
Developmental Patterns of Catechol-O-Methyltransferase in Genetically Different Rat Strains: Enzymatic and Immunochemical Studies 总被引:4,自引:4,他引:0
D. J. Goldstein R. M. Weinshilboum J. H. Dunnette C. R. Creveling 《Journal of neurochemistry》1980,34(1):153-162
Abstract: Catechol- O -methyltransferase (COMT) activity in the liver and kidneys of adult Fischer-344 (F-344) rats is only half of that in the same organs of Wistar-Furth (W-F) rats. The trait of low COMT activity in these animals is inherited in an autosomal recessive fashion. A comprehensive study of patterns of change in COMT activity during growth and development was performed to determine whether "temporal gene" effects might play a role in the inherited differences in enzyme activity present in adult animals. The COMT activity expressed per mg protein in liver and kidneys of newborn F-344 rats is only 50–60% of that in the same organs of W-F animals. The liver and the kidneys of newborn rats of both strains have COMT activity an order of magnitude higher than those in brain, heart, or blood. In addition, in both strains there are much larger increases in liver and kidney COMT activities during growth and development (5–10 fold) than in blood, brain, or heart (one- to twofold). Immunotitration with antibodies against rat COMT demonstrates that differences in immunoreactive COMT parallel differences in COMT activity, both between strains and within strains during growth and development. However, when the temporal patterns of change in enzyme activities in the liver and the kidneys of the two strains of rat are compared at multiple times during growth and development, no differences in the patterns are present. These results make it unlikely that temporal gene effects can explain the inherited differences in COMT activity in liver and kidneys of F-344 and W-F rats. 相似文献
266.
267.
268.
269.
J. E. D. Fox 《Economic botany》1971,25(3):221-233
270.