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   116篇
  免费   6篇
综合类   13篇
畜牧兽医   106篇
园艺   1篇
植物保护   2篇
  2017年   4篇
  2016年   1篇
  2015年   1篇
  2014年   3篇
  2013年   16篇
  2011年   1篇
  2010年   3篇
  2009年   1篇
  2008年   2篇
  2007年   10篇
  2006年   2篇
  2004年   2篇
  2003年   6篇
  2002年   4篇
  2001年   3篇
  2000年   5篇
  1999年   2篇
  1998年   16篇
  1997年   2篇
  1996年   6篇
  1995年   2篇
  1994年   1篇
  1993年   5篇
  1992年   1篇
  1991年   5篇
  1990年   2篇
  1989年   6篇
  1988年   5篇
  1983年   4篇
  1982年   1篇
排序方式: 共有122条查询结果,搜索用时 31 毫秒
81.
The objectives of the current study were to determine how intermittent suckling (IS) affects nursing behavior, litter activity, and general behavioral patterns during lactation, and whether IS during an extended lactation period results in behavioral patterns associated with piglet distress. Intermittent suckling was applied either with 6-h separation intervals (IS6) or with 12-h separation intervals (IS12) and was compared with the conventional treatment (CT). In the CT (n = 17 litters), sows were continuously present until weaning (d 21, d 0 = farrowing). In both IS6 and IS12, sows were separated from their litter for 12 h/d, beginning at d 14 and lasting until weaning (d 43 +/- 1 d). In IS6, litters (n = 14) and sows were separated from 0800 to 1400 and from 2000 to 0200; in IS12 litters (n = 14) and sows were separated between 0800 and 2000. In IS litters, the activity pattern over the 24-h cycle was markedly changed by IS; litter activity was lower (P < 0.001) during sow absence and greater (P < 0.001) during sow presence compared with the unweaned CT litters. Moreover, both total nursing frequency (P < 0.001) and the percentage (P < 0.002) of successful nursings were reduced by IS. Although total nursing frequency was greater in IS6 compared with IS12 (on d 21 and 28), no differences in the frequency of successful nursings existed between IS6 and IS12 from d 14 onward. Eating behavior was increased shortly after the onset of IS (d 17) in both IS6 (P = 0.059) and IS12 (P < 0.001) compared with the unweaned CT litters. The IS12 litters showed more eating behavior compared with IS6 and their exploratory behavior increased in time (P < 0.001), whereas IS6 showed more nursing behavior. Aggressive or manipulative behavior of both IS treatments was similar compared with the unweaned CT, and remained relatively unaltered with time in IS12 and IS6. Weaning in the CT resulted in more manipulative (P < 0.001) and aggressive (P = 0.004) behavior compared with pre-weaning values. Intermittent suckling may contribute to adaptation to the postweaning state by stimulating eating behavior, without causing obvious behavioral distress.  相似文献   
82.
In model terrestrial ecosystems maintained for three plant generations at elevated concentrations of atmospheric carbon dioxide, increases in photosynthetically fixed carbon were allocated below ground, raising concentrations of dissolved organic carbon in soil. These effects were then transmitted up the decomposer food chain. Soil microbial biomass was unaffected, but the composition of soil fungal species changed, with increases in rates of cellulose decomposition. There were also changes in the abundance and species composition of Collembola, fungal-feeding arthropods. These results have implications for long-term feedback processes in soil ecosystems that are subject to rising global atmospheric carbon dioxide concentrations.  相似文献   
83.
84.
85.
冬季日光温室的保温措施及对天气性灾害的预防对策   总被引:1,自引:0,他引:1  
高效节能日光温室以太阳能为主要能源 ,不加温或临时加温就能进行果菜类生产 ,但近几年发展的温室偏高偏宽 ,保温措施又跟不上 ,结果在1 999年冬至 2 0 0 0年春雪多、严寒的条件下 ,不少温室出现了 2℃以下低温 ,甚至冻害 ,使果菜类生产受到很大影响 ,造成了很大的损失。对此 ,我站经过试验和调研 ,提出如下的保温措施及对天气灾害性的对策 ,使果菜类冬季能在日光温室得以正常生长 ,进一步提高冬季蔬菜生产的经济效益和社会效益 ,保证我市保护地蔬菜生产持续发展。1 温室结构与保温的关系沈阳市地处北纬 41°以北 ,冬至太阳高度角低 ,中午 …  相似文献   
86.
87.
The effect of flunixin meglumine and flurbiprofen on the course of experimental Escherichia coli mastitis was examined. Nine cows (within one month post partum) were inoculated intramammarily with 20 x 10(5) viable E coli in both rear quarters. Three cows remained untreated (controls); three cows received three injections of flunixin meglumine and three cows received flurbiprofen as two intravenous infusions. Flunixin meglumine and flurbiprofen were initially given before clinical signs were observed. Treatment was repeated if the cows' temperature increased by more than 1 degree C. In the untreated cows, rectal temperature and heart rate increased from three hours after infection, and rumen motility (both frequency and amplitude) decreased from four hours after infection. Treatment with flunixin meglumine or flurbiprofen almost completely abolished the febrile response during the first nine hours after infection, and the decrease in rumen motility was less pronounced in the treated animals. These results suggest that the decrease in rumen motility during E coli mastitis is at least partly due to a mechanism involving prostaglandin.  相似文献   
88.
89.
Summary

Faecal samples from suckling piglets from 113 litters on 25 farms in the Netherlands were examined to study the prevalence of gastrointestinal parasites, in particular Strongyloides ransomi and Isospora suis. S. ransomi was not found but I. suis was demonstrated in 17 of the 25 farms and in 41 out of 77 litters of these farms (53%). No other parasites were found. On the basis of these results, a longitudinal study on the incidence and significance of I. suis was performed on 10 farms (5 litters/farm). I. suis was found on 9 out of 10 farms and in 56% of the litters. Farms differed in infection levels, measured as the numbers of patent litters, and in the onset of patency. Other parasites were only found in faecal samples from the sows and from farrowing pens. These were, in order of prevalence, Balantidium coli, Ascaris suum, Eimeria spinosa, E. debliecki and E. suis.  相似文献   
90.
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