收费全文 | 259565篇 |
免费 | 15565篇 |
国内免费 | 654篇 |
林业 | 23929篇 |
农学 | 14144篇 |
基础科学 | 2964篇 |
44358篇 | |
综合类 | 25470篇 |
农作物 | 17407篇 |
水产渔业 | 17195篇 |
畜牧兽医 | 99606篇 |
园艺 | 6379篇 |
植物保护 | 24332篇 |
2021年 | 2597篇 |
2020年 | 2981篇 |
2019年 | 3740篇 |
2018年 | 4233篇 |
2017年 | 4634篇 |
2016年 | 4999篇 |
2015年 | 4448篇 |
2014年 | 5834篇 |
2013年 | 16486篇 |
2012年 | 6725篇 |
2011年 | 8651篇 |
2010年 | 7498篇 |
2009年 | 8046篇 |
2008年 | 7921篇 |
2007年 | 7015篇 |
2006年 | 7574篇 |
2005年 | 6787篇 |
2004年 | 6567篇 |
2003年 | 6352篇 |
2002年 | 5648篇 |
2001年 | 6244篇 |
2000年 | 5848篇 |
1999年 | 5486篇 |
1998年 | 4160篇 |
1997年 | 4198篇 |
1996年 | 3923篇 |
1995年 | 4510篇 |
1994年 | 3889篇 |
1993年 | 3633篇 |
1992年 | 4389篇 |
1991年 | 4442篇 |
1990年 | 4177篇 |
1989年 | 4226篇 |
1988年 | 3688篇 |
1987年 | 3796篇 |
1986年 | 3753篇 |
1985年 | 4035篇 |
1984年 | 3698篇 |
1983年 | 3511篇 |
1982年 | 2900篇 |
1981年 | 2824篇 |
1980年 | 2777篇 |
1979年 | 3123篇 |
1978年 | 2847篇 |
1977年 | 2659篇 |
1976年 | 2468篇 |
1975年 | 2312篇 |
1974年 | 2517篇 |
1973年 | 2512篇 |
1972年 | 2234篇 |
2. Extracts from the abdominal fat of 160 carcases and of the experimental foods were analysed for fatty acids by gas liquid chromatography.
3. Birds reared in HT had a significantly lower proportion of polyun‐saturated fatty acids (PUFA) in their abdominal fat between 34 and 54 d than birds in LT. The depot fat contents of oleic, linoleic and linolenic acids were all reduced by HT at 54 d.
4. For broilers slaughtered at 54 d, saturated fatty acid (SFA) content was much higher in females at high temperatures than in males while at low temperatures PUFA, especially linoleic, was much lower in males than in females.
5. Early finishing of broilers is advantageous from the viewpoint of fatty acid composition because the PUFA/SFA ratio declines significantly with age regardless of temperature. 相似文献
2. Neither of the peptides, at any dose, affected cardiovascular functions, plasma ions and osmolality. Infusion of MT at the rate of 10 mU/min/kg body weight increased respiratory rate. Both peptides at doses of 1 and 10 mU/min/kg reduced the temperatures of the comb and shank but had no effect on the skin and cloaca.
3. Doses of 0.1 and 1.0 mU MT/mu/kg reduced plasma aldosterone and at 10 mU/min/kg increased plasma AVT. At any given dose MT had no effect on plasma prolactin. AVT at 0.1 and 1.0 mU/min/kg of AVT reduced plasma MT. AVT at 1.0 mU/min/kg increased plasma prolactin and at 10 mU/min/kg reduced plasma aldosterone.
4. During saline infusion, plasma MT was positively correlated with plasma AVT and negatively correlated with respiratory rate and cloacal temperature. Plasma AVT showed a positive correlation with plasma MT and aldosterone and a negative correlation with respiratory rate and skin temperature.
5. During saline infusion, there was no significant correlation between cardiovascular functions, or plasma osmolality and ionic composition and plasma MT or AVT.
6. The present study suggests that interrelationships between circulating concentrations of AVT and MT do exist and that AVT affects 相似文献