全文获取类型
收费全文 | 25043篇 |
免费 | 1289篇 |
国内免费 | 10篇 |
专业分类
林业 | 899篇 |
农学 | 755篇 |
基础科学 | 156篇 |
3651篇 | |
综合类 | 3540篇 |
农作物 | 917篇 |
水产渔业 | 1348篇 |
畜牧兽医 | 13242篇 |
园艺 | 273篇 |
植物保护 | 1561篇 |
出版年
2019年 | 251篇 |
2018年 | 420篇 |
2017年 | 510篇 |
2016年 | 472篇 |
2015年 | 339篇 |
2014年 | 463篇 |
2013年 | 972篇 |
2012年 | 803篇 |
2011年 | 961篇 |
2010年 | 693篇 |
2009年 | 675篇 |
2008年 | 975篇 |
2007年 | 923篇 |
2006年 | 816篇 |
2005年 | 740篇 |
2004年 | 650篇 |
2003年 | 711篇 |
2002年 | 614篇 |
2001年 | 809篇 |
2000年 | 801篇 |
1999年 | 634篇 |
1998年 | 275篇 |
1997年 | 284篇 |
1995年 | 260篇 |
1994年 | 229篇 |
1993年 | 234篇 |
1992年 | 426篇 |
1991年 | 518篇 |
1990年 | 437篇 |
1989年 | 413篇 |
1988年 | 404篇 |
1987年 | 411篇 |
1986年 | 367篇 |
1985年 | 390篇 |
1984年 | 341篇 |
1983年 | 287篇 |
1982年 | 247篇 |
1979年 | 386篇 |
1978年 | 291篇 |
1977年 | 291篇 |
1976年 | 302篇 |
1975年 | 321篇 |
1974年 | 333篇 |
1973年 | 302篇 |
1972年 | 290篇 |
1971年 | 246篇 |
1969年 | 290篇 |
1968年 | 269篇 |
1967年 | 327篇 |
1966年 | 306篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
81.
M I Banton S S Nicholson P L Jowett M B Brantley C L Boudreaux 《Journal of the American Veterinary Medical Association》1987,191(7):827-828
Cattle from 2 herds developed copper toxicosis after the ingestion of chicken litter. The affected animals were adult Holstein cows and crossbred steers that ate 9 to 16 kg of litter/day. These cattle developed a sudden onset of weakness, depression, anorexia, icteric mucous membranes, and dark reddish brown urine. Liver copper concentrations in 2 cattle (1 from each herd) were 436 and 730 ppm. Results of copper analyses of chicken litter ranged from 620 to 920 ppm. Sodium molybdate and sodium thiosulfate were added to the ration of the dairy herd. Two cows with clinical signs of copper toxicosis recovered after being given additional sodium molybdate and thiosulfate supplements, orally. 相似文献
82.
83.
1. The endogenous avian leukosis virus (ev) loci present in 9 lines of domestic fowls have been partially characterised and the average heterozygosity of the loci in each line calculated. 2. Using these data an estimate of the coefficient of inbreeding of the lines was derived; this estimate of the extent of inbreeding is compared with the mating history of the lines. 3. This method provides the first means of directly assessing the degree of inbreeding of fowl lines: assumptions implicit in the method are discussed. 相似文献
84.
Two miniature Shetland ponies showing clinical signs of Digitalis purpurea (foxglove) poisoning were examined. One animal died shortly afterwards, but the second was treated successfully with the anti-arrhythmic agent, phenytoin, and was discharged after 16 days. 相似文献
85.
86.
I Gunsser T H?nichen J Maierl 《Tier?rztliche Praxis. Ausgabe G, Grosstiere/Nutztiere》1999,27(3):187-192
In Llamas and Alpacas infestation with Fasciola hepatica or Dicrocoelium dendriticum can cause liver damage, sometimes even with lethal outcome. Once infected South American Camelids (SACs) react more sensitively to these parasites than other domestic ruminants. We report here on the pathology, parasitology, clinics and therapy of this disease. Concerning Dicrocoelium dendriticum we describe own clinical results and therapeutic outcome in addition to the pathological investigation. According to anatomic corrosion casts, the bile ducts of SACs show more similarity with the equine bile system than with the bile system of domestic ruminants. 相似文献
87.
88.
89.
90.