全文获取类型
| 收费全文 | 26053篇 |
| 免费 | 240篇 |
| 国内免费 | 168篇 |
专业分类
| 林业 | 1056篇 |
| 农学 | 240篇 |
| 基础科学 | 107篇 |
| 3583篇 | |
| 综合类 | 6050篇 |
| 农作物 | 829篇 |
| 水产渔业 | 278篇 |
| 畜牧兽医 | 13366篇 |
| 园艺 | 156篇 |
| 植物保护 | 796篇 |
出版年
| 2023年 | 39篇 |
| 2016年 | 52篇 |
| 2015年 | 58篇 |
| 2014年 | 76篇 |
| 2013年 | 85篇 |
| 2012年 | 2182篇 |
| 2011年 | 2502篇 |
| 2010年 | 528篇 |
| 2009年 | 383篇 |
| 2008年 | 2140篇 |
| 2007年 | 2191篇 |
| 2006年 | 1938篇 |
| 2005年 | 1945篇 |
| 2004年 | 1814篇 |
| 2003年 | 1654篇 |
| 2002年 | 1515篇 |
| 2001年 | 1016篇 |
| 2000年 | 1294篇 |
| 1999年 | 504篇 |
| 1998年 | 95篇 |
| 1997年 | 85篇 |
| 1996年 | 110篇 |
| 1995年 | 167篇 |
| 1994年 | 162篇 |
| 1993年 | 173篇 |
| 1992年 | 187篇 |
| 1991年 | 202篇 |
| 1990年 | 214篇 |
| 1989年 | 172篇 |
| 1988年 | 185篇 |
| 1987年 | 194篇 |
| 1986年 | 156篇 |
| 1985年 | 128篇 |
| 1984年 | 165篇 |
| 1983年 | 144篇 |
| 1982年 | 115篇 |
| 1981年 | 84篇 |
| 1980年 | 78篇 |
| 1979年 | 76篇 |
| 1978年 | 37篇 |
| 1976年 | 46篇 |
| 1974年 | 43篇 |
| 1970年 | 40篇 |
| 1963年 | 69篇 |
| 1960年 | 40篇 |
| 1959年 | 44篇 |
| 1958年 | 44篇 |
| 1957年 | 69篇 |
| 1954年 | 40篇 |
| 1953年 | 37篇 |
排序方式： 共有10000条查询结果，搜索用时 15 毫秒
101.
102.
Slocombe JO Villeneuve A 《The Canadian veterinary journal. La revue veterinaire canadienne》1993,34(10):630-633
In late November 1991, 1883 clinics in Canada were sent a questionnaire to assess the status of Dirofilaria immitis in dogs in 1991 and there was a 60.0% response. There were 344,031 dogs tested for heart-worm (HW), 627 were found infected and the prevalence of HW infection was 0.18%. There were 417 dogs with HW in Ontario, 116 in Manitoba, 38 in Quebec, 53 in British Columbia, three in Alberta, and one in Nova Scotia. In British Columbia, all of the infected dogs but one were from the Okanagan valley which, as from 1991, is a new focus of infection in Canada. Most dogs with HW had not been on preventive medication in 1990, and the prevalence among dogs tested and unprotected was 0.59%. That prevalence was considerably higher in endemic areas. Companion dogs, over three years of age and maintained primarily outdoors in rural areas, were most frequently infected. One cat was diagnosed with D. immitis and 33 dogs had Dipetalonema reconditium. 相似文献
103.
104.
Hathaway SC Bullians JA Johnstone AC Biss ME Thompson A 《New Zealand veterinary journal》1993,41(4):166-170
Omphalophlebitis, generally referred to as navel ill, is a common post-mortem meat inspection finding in very young calves slaughtered in New Zealand, and a gross pathological, histopathological and bacteriological evaluation of 147 carcasses condemned for this condition at routine post-mortem meat inspection was undertaken. Localised lesions restricted to the umbilicus alone were present in 29.9% of cases. The majority of cases included gross pathological change in the umbilical vessels and other tissue sites beyond the umbilicus. Most hepatic nodes were grossly normal but histological examination revealed that 61.5% of nodes from other than localised cases of navel ill were hyperplastic. However, there was little difference in the prevalence of hyperplastic hepatic nodes from cases of localised navel ill (21.4%) compared with normal calves (15.9%). Despite the wide range of bacteria isolated from umbilical lesions, Salmonella typhimurium recovered from the navel, liver and hepatic nodes of a single extended case of navel ill was the only isolation of known public health importance. Given the separation of cases of navel ill into different gross pathological, histopathological and microbiological categories, current meat inspection judgments whereby all calves with navel ill are condemned should be revised. In particular, routine condemnation of the carcass and viscera in all cases of localised navel ill (lesions restricted to the umbilicus alone) should be reassessed. 相似文献
105.
Finkbeiner A 《Science (New York, N.Y.)》1993,262(5142):1969-1970
106.
107.
Lawler A 《Science (New York, N.Y.)》1995,269(5231):1665
108.
Regalado A 《Science (New York, N.Y.)》1995,268(5216):1436-1437
109.
110.