| 收费全文 | 7157篇 |
| 免费 | 374篇 |
| 国内免费 | 840篇 |
| 林业 | 930篇 |
| 农学 | 1168篇 |
| 基础科学 | 568篇 |
| 1311篇 | |
| 综合类 | 1989篇 |
| 农作物 | 435篇 |
| 水产渔业 | 318篇 |
| 畜牧兽医 | 855篇 |
| 园艺 | 252篇 |
| 植物保护 | 545篇 |
| 2024年 | 16篇 |
| 2023年 | 48篇 |
| 2022年 | 194篇 |
| 2021年 | 284篇 |
| 2020年 | 269篇 |
| 2019年 | 274篇 |
| 2018年 | 183篇 |
| 2017年 | 248篇 |
| 2016年 | 230篇 |
| 2015年 | 312篇 |
| 2014年 | 280篇 |
| 2013年 | 365篇 |
| 2012年 | 442篇 |
| 2011年 | 460篇 |
| 2010年 | 438篇 |
| 2009年 | 438篇 |
| 2008年 | 378篇 |
| 2007年 | 373篇 |
| 2006年 | 436篇 |
| 2005年 | 417篇 |
| 2004年 | 205篇 |
| 2003年 | 153篇 |
| 2002年 | 117篇 |
| 2001年 | 134篇 |
| 2000年 | 153篇 |
| 1999年 | 217篇 |
| 1998年 | 172篇 |
| 1997年 | 157篇 |
| 1996年 | 136篇 |
| 1995年 | 116篇 |
| 1994年 | 108篇 |
| 1993年 | 110篇 |
| 1992年 | 104篇 |
| 1991年 | 73篇 |
| 1990年 | 82篇 |
| 1989年 | 76篇 |
| 1988年 | 55篇 |
| 1987年 | 38篇 |
| 1986年 | 25篇 |
| 1985年 | 16篇 |
| 1984年 | 10篇 |
| 1983年 | 5篇 |
| 1982年 | 12篇 |
| 1981年 | 6篇 |
| 1980年 | 4篇 |
| 1979年 | 2篇 |
The effects of 5 different feeding systems on the performance, carcass traits and organ development were studied in pigeon squabs.
The 5 treatments were (1) whole grains of maize, pea and wheat plus concentrate feed; (2)whole grains of maize and wheat plus concentrate feed (CWC); (3) whole grains of maize and pea plus concentrate feed; (4)whole grain of maize plus concentrate feed (CC); and (5) compound feed (CF).
Feed intake of parent pigeons increased significantly from 0 to 21 d and it was higher in the CF treatment. Body weight of squabs in the CWC treatment was the highest among the 5 treatments in 4 weeks. Body weight losses of parental pigeons during the rearing period were not significantly different among the 5 treatments.
Protein intake in CC and CWC treatments was lower than that of the other three treatments. The CWC treatment had the highest daily weight gain and the lowest feed conversion ratio. Treatments were statistically similar in the relative weight of carcass, breast and thigh. CF had the lower relative weight of abdominal fat.
Relative weight of gizzard in the CF treatment was significantly lower than that of CWC.
It was concluded that the application of free choice feeding of whole grains of maize and wheat plus concentrate feed increased the body weight of 28-d-old pigeon squabs and decreased the feed conversion rate of parent pigeons. This feeding strategy could be commercially interesting in meat-type pigeon production.