首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   185篇
  免费   9篇
林业   8篇
农学   15篇
基础科学   1篇
  45篇
综合类   11篇
农作物   33篇
水产渔业   20篇
畜牧兽医   41篇
园艺   2篇
植物保护   18篇
  2024年   1篇
  2023年   1篇
  2022年   6篇
  2021年   12篇
  2020年   5篇
  2019年   3篇
  2018年   6篇
  2017年   9篇
  2016年   3篇
  2015年   7篇
  2014年   7篇
  2013年   16篇
  2012年   9篇
  2011年   12篇
  2010年   6篇
  2009年   7篇
  2008年   5篇
  2007年   3篇
  2006年   4篇
  2005年   8篇
  2004年   2篇
  2003年   7篇
  2002年   2篇
  2001年   4篇
  2000年   3篇
  1999年   3篇
  1998年   2篇
  1997年   5篇
  1996年   1篇
  1995年   3篇
  1994年   2篇
  1993年   3篇
  1991年   1篇
  1990年   3篇
  1989年   2篇
  1987年   2篇
  1986年   3篇
  1985年   1篇
  1984年   6篇
  1983年   3篇
  1982年   2篇
  1981年   1篇
  1978年   3篇
排序方式: 共有194条查询结果,搜索用时 109 毫秒
191.
Results are reported on the nutritional quality of prickly pear seeds,Opuntia ficus-indica. The seeds contained 16.6% protein, 17.2% fat, 49.6% fiber and 3.0% ash. The meal showed a high amount of iron (9.45 mg %). The contents of Mg, P, K, Zn and Cu were nutritionally significant contributing approximately 10–20% of the Recommended Dietary Allowances (RDA) of these elements per 100 g of dry weight. The amount of Ca represented less than 10% of the RDA for that element. Aspartic acid, glutamic acid, arginine and glycine were the most abundant amino acids making nearly half of the total amino acids content. The seeds were rich in sulfur amino acids (methionine + cystine). Lysine was the first limiting amino acid resulting in a chemical score of 62 for the protein. The in-vitro protein digestibility and the calculated protein efficiency ratio were 77% and 1.82 compared to 90% and 2.50, respectively, for ANRC casein.  相似文献   
192.
A four-year crossing scheme involving Spanish V line (V) and Egyptian Baladi Red (B) rabbits was carried out to produce five genetic groups: V, B, 1/2B1/2V(F1), (1/2B1/2V)2(F2), and ((1/2B1/2V)2)2. The last genetic group was considered a new line, named APRI. Body weights (BW) and daily gains in weight (DG) from four to twelve weeks were evaluated for 13,383 rabbits produced by 330 sires and 1074 dams. An animal model was used to estimate heritabilities and common litter effects and a generalized least squares procedure was used to estimate direct additive effects, and direct and maternal heterosis.Heritabilities for growth traits were mostly moderate, ranging from 0.075 to 0.240 for BW and from 0.020 to 0.104 for DG. The V line was heavier and had better gains at each weighing than B rabbits. The F2 and APRI were also lower in most post-weaning growth performance measures than V line rabbits. APRI rabbits were significantly lighter by 39, 26, 46, 64, and 50 g at ages of 4, 6, 8, 10, and 12 weeks, respectively, relative to the purebred V line, while APRI was significantly heavier by 36 and 127 g relative to the B line at 4 and 12 weeks. The V line, in general, had a higher DG than B line. The differences were 3.15, 7.91 and 1.95 g/d at age intervals of 8–10, 10–12 and 4–12 weeks. Differences in direct additive effects between the two lines were in favor of V line rabbits reaching 15.0% (76 g) at 4 weeks and 13.3% (195 g) at 12 weeks. Direct additive effects for DG were significant during most age intervals reaching 35.7% (7.19 g/d) in the interval of 10–12 weeks. All estimates of direct heterosis were positive and ranged from 4.9 to 16.7% for BW and 14.4 to 29.5% for DG, but the estimates for maternal heterosis were, in most cases, significantly negative and ranging from − 4.5 to − 15.2% for BW and from 20.6 to − 36.9% for DG. If the results are confirmed at commercial farms, the APRI line could be reared in heat stress conditions.  相似文献   
193.
Misaki feral horses were separated into 2 herds and the difference between dispersal from natal group (natal dispersal) and dispersal from natal area (natal emigration) was studied. The causes of dispersal and emigration and their effects on harem formation were studied 1979-1994. The number of horses ranged from 73 (mature males: 8, mature females: 26, young males: 8, young females: 3, colt foals: 6, filly foals: 10 and geldings: 12) in 1979 and 86 (mature males: 14, mature females: 37, young males: 12, young females: 7, colt foals: 5, filly foals: 7 and geldings: 4) in 1994 when the present study ended. All 29 males which survived to age 4 years and 58 females which survived to age 3 years left their natal or mother groups at age one to 3. Seventeen of 22 dispersing males and 29 of 39 dispersing females left their natal groups around the birth of their siblings and significant correlations were found between natal dispersal and birth of a sibling. The number of emigrating young males correlated negatively and significantly with the total number of young males in another herd and the number of emigrating young females correlated positively and significantly with the total number of young females in the natal herd. All 13 emigrating stallions which survived to age 5 years formed stable harem groups and a significant correlation was found between natal emigration and harem formation. Twenty-three of 35 resident mares formed stable consort relations with harem stallions and a significant correlation was found between residence and formation of stable consort relations.  相似文献   
194.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号