收费全文 | 3441篇 |
免费 | 175篇 |
国内免费 | 407篇 |
林业 | 495篇 |
农学 | 578篇 |
基础科学 | 281篇 |
637篇 | |
综合类 | 902篇 |
农作物 | 154篇 |
水产渔业 | 86篇 |
畜牧兽医 | 573篇 |
园艺 | 97篇 |
植物保护 | 220篇 |
2024年 | 2篇 |
2023年 | 38篇 |
2022年 | 94篇 |
2021年 | 140篇 |
2020年 | 130篇 |
2019年 | 118篇 |
2018年 | 115篇 |
2017年 | 137篇 |
2016年 | 112篇 |
2015年 | 162篇 |
2014年 | 159篇 |
2013年 | 176篇 |
2012年 | 221篇 |
2011年 | 203篇 |
2010年 | 212篇 |
2009年 | 225篇 |
2008年 | 185篇 |
2007年 | 211篇 |
2006年 | 176篇 |
2005年 | 165篇 |
2004年 | 83篇 |
2003年 | 71篇 |
2002年 | 75篇 |
2001年 | 87篇 |
2000年 | 88篇 |
1999年 | 89篇 |
1998年 | 87篇 |
1997年 | 64篇 |
1996年 | 63篇 |
1995年 | 66篇 |
1994年 | 43篇 |
1993年 | 60篇 |
1992年 | 38篇 |
1991年 | 33篇 |
1990年 | 28篇 |
1989年 | 20篇 |
1988年 | 17篇 |
1987年 | 7篇 |
1986年 | 5篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1976年 | 1篇 |
1954年 | 1篇 |
1950年 | 1篇 |
1935年 | 1篇 |
2. In the first experiment, removal of food for 8 h/d from 42 to 56 d of age significantly improved food conversion efficiency of broilers on deep litter. Removal of food for 16 h/d or on alternate days tended to cause slower growth and also improved conversion efficiency.
3. In the second experiment, denial of food for 8 h/d did not significantly affect either growth rate or conversion efficiency of caged broilers. Denial of food on alternate days, from 28 d of age, depressed food intake and growth rate. Food restriction decreased dressing percentage regardless of the age of introduction. With 32, 40 or 48 h food denial each 72 h there was a large depression in growth rate and dressing percentage. Carcass dry matter was also less, indicating less carcass fat, when food was denied for 48 h each 72 h.
4. In the third experiment, growth rate of broilers on deep litter was significantly improved by denying food for 8 h/d from 28 d of age, and was significantly depressed by food denial on alternate days. This depression was significantly more severe if restriction started at 28 d rather than at 42 d of age. Conversion efficiency was not significantly improved by denial for 8 h/d.
5. In the last two experiments conversion efficiency was much worse in severe restriction. 相似文献
2. Live‐weight gains, from 8 to 63 d, were depressed when the diet contained 150 g RSM/kg and there was a highly significant negative correlation between weight gain and inclusion rate of RSM over this period.
3. The efficiency of food utilisation was worse when the diet included 150 g solvent RSM/kg than when it contained no RSM: food efficiency was consistently poorer whenever RSM was included in the diet but the difference was significant only when the diet contained 10 g tallow/kg.
4. Carcasses from birds fed on diets containing 10 g tallow/kg had a better appearance than those from birds on diets containing 30 g tallow/kg, while the flavour of meat from birds fed on a diet containing 150 g solvent RSM/kg treatment was adversely affected. However, up to 100 g solvent RSM/kg may be included in broiler diets without affecting appearance, taste, texture or acceptability of the meat.
5. Inclusion of 50 g or more, solvent RSM/kg reduced growth rate and worsened food efficiency. 相似文献
Funding: Self-funded. 相似文献