全文获取类型
收费全文 | 150782篇 |
免费 | 7623篇 |
国内免费 | 92篇 |
专业分类
林业 | 6396篇 |
农学 | 4333篇 |
基础科学 | 1029篇 |
16237篇 | |
综合类 | 32000篇 |
农作物 | 6038篇 |
水产渔业 | 6403篇 |
畜牧兽医 | 75650篇 |
园艺 | 1711篇 |
植物保护 | 8700篇 |
出版年
2018年 | 1608篇 |
2017年 | 1738篇 |
2016年 | 1688篇 |
2014年 | 1664篇 |
2013年 | 5275篇 |
2012年 | 3426篇 |
2011年 | 4210篇 |
2010年 | 2777篇 |
2009年 | 2712篇 |
2008年 | 4216篇 |
2007年 | 3917篇 |
2006年 | 3822篇 |
2005年 | 3632篇 |
2004年 | 3687篇 |
2003年 | 3699篇 |
2002年 | 3575篇 |
2001年 | 4271篇 |
2000年 | 4229篇 |
1999年 | 3270篇 |
1997年 | 1458篇 |
1995年 | 1662篇 |
1994年 | 1564篇 |
1993年 | 1502篇 |
1992年 | 3176篇 |
1991年 | 3440篇 |
1990年 | 3428篇 |
1989年 | 3483篇 |
1988年 | 3210篇 |
1987年 | 3288篇 |
1986年 | 3408篇 |
1985年 | 3314篇 |
1984年 | 2692篇 |
1983年 | 2469篇 |
1982年 | 1682篇 |
1981年 | 1602篇 |
1980年 | 1491篇 |
1979年 | 2536篇 |
1978年 | 2065篇 |
1977年 | 1757篇 |
1976年 | 1674篇 |
1975年 | 1824篇 |
1974年 | 2326篇 |
1973年 | 2353篇 |
1972年 | 2386篇 |
1971年 | 2295篇 |
1970年 | 2148篇 |
1969年 | 1906篇 |
1968年 | 1531篇 |
1967年 | 1710篇 |
1966年 | 1502篇 |
排序方式: 共有10000条查询结果,搜索用时 937 毫秒
911.
The winter flounder, Pseudopleuronectes americanus, is an esteemed food fish and has sustained an important commercial and recreational fishery for many years in the northeastern United States. Histopathologic examinations of hepatic tissues of winter flounder from Boston Harbor revealed a high prevalence of neoplasms. The lesions, designated as cholangiocarcinomas and hepatocarcinomas, were found in 16 of 200 fish examined and resembled those experimentally induced in rodents by exposure to carcinogens. 相似文献
912.
Sorkin RD 《Science (New York, N.Y.)》1985,228(4699):572
913.
914.
915.
916.
917.
Brill WJ 《Science (New York, N.Y.)》1985,229(4709):115-118
918.
Assaf R Turgeon D St-Jacques C Hamelin C 《The Canadian veterinary journal. La revue veterinaire canadienne》1985,26(7):209-211
For the first time in Quebec, a type 1 canine adenovirus was isolated in cell culture and typed by restriction endonuclease analysis. This virus originated from the internal organs of a young dog killed by a severe respiratory disease without showing any sign of hepatitis. 相似文献
919.
920.
Evaluation of a Killed Vaccine Against Porcine Pleuropneumonia Due to Haemophilus pleuropneumoniae 总被引:20,自引:2,他引:18
Higgins R Larivière S Mittal KR Martineau GP Rousseau P Cameron J 《The Canadian veterinary journal. La revue veterinaire canadienne》1985,26(2):86-89
A bacterin containing serotypes 1 and 5 of Haemophilus pleuropneumoniae was developed for the prevention and the control of porcine pleuropneumonia. It was injected intramuscularly into three groups of ten piglets, the first group with one dose, the second one with two doses and the third one with three doses at two-week intervals. Another group of ten piglets did not receive the vaccine. All the piglets were then challenged by an aerosol of mixed suspensions of H. pleuropneumoniae serotypes 1 and 5. Two and three injections of vaccine completely prevented mortality, whereas half of the control piglets and of those receiving only one dose of vaccine died. All surviving piglets, both control and vaccinated, had severe signs of respiratory disease for at least 36 hours after exposure to challenge. Moreover, vaccination did not induce the production of antibodies at high titers. Local reactions were not noted after vaccination and at postmortem; ten weeks after the challenge, there were no signs of abscess formation or induration. 相似文献