全文获取类型
收费全文 | 1236篇 |
免费 | 73篇 |
专业分类
林业 | 50篇 |
农学 | 24篇 |
基础科学 | 7篇 |
118篇 | |
综合类 | 261篇 |
农作物 | 46篇 |
水产渔业 | 43篇 |
畜牧兽医 | 653篇 |
园艺 | 22篇 |
植物保护 | 85篇 |
出版年
2019年 | 22篇 |
2018年 | 11篇 |
2017年 | 19篇 |
2016年 | 18篇 |
2015年 | 19篇 |
2014年 | 21篇 |
2013年 | 29篇 |
2012年 | 39篇 |
2011年 | 46篇 |
2010年 | 24篇 |
2009年 | 18篇 |
2008年 | 41篇 |
2007年 | 29篇 |
2006年 | 48篇 |
2005年 | 43篇 |
2004年 | 33篇 |
2003年 | 36篇 |
2002年 | 29篇 |
2001年 | 29篇 |
2000年 | 25篇 |
1999年 | 26篇 |
1998年 | 12篇 |
1997年 | 13篇 |
1996年 | 13篇 |
1995年 | 19篇 |
1994年 | 16篇 |
1993年 | 11篇 |
1992年 | 26篇 |
1991年 | 29篇 |
1990年 | 25篇 |
1989年 | 29篇 |
1988年 | 22篇 |
1987年 | 14篇 |
1986年 | 17篇 |
1985年 | 26篇 |
1984年 | 24篇 |
1983年 | 16篇 |
1979年 | 16篇 |
1978年 | 16篇 |
1977年 | 15篇 |
1975年 | 15篇 |
1974年 | 16篇 |
1973年 | 12篇 |
1972年 | 18篇 |
1971年 | 10篇 |
1970年 | 14篇 |
1969年 | 12篇 |
1968年 | 10篇 |
1967年 | 11篇 |
1966年 | 10篇 |
排序方式: 共有1309条查询结果,搜索用时 15 毫秒
51.
52.
Plasma enteroglucagon and neurotensin levels in gnotobiotic calves infected with enteropathogenic and non-enteropathogenic viruses 总被引:1,自引:0,他引:1
G A Hall K R Parsons J C Bridger M A Ghatei Y C Ying S R Bloom 《Research in veterinary science》1985,38(1):99-103
Five gnotobiotic calves were each infected with five viruses. Each calf was inoculated with coronavirus at seven days old, followed by astrovirus, Newbury agent, parainfluenzavirus type 3 and rotavirus at intervals of two weeks. Three of the viruses were enteropathogenic (bovine coronavirus, bovine calici-like virus and bovine rotavirus) and two were not (bovine astrovirus and parainfluenzavirus type 3). Plasma levels of the peptide hormones enteroglucagon and neurotensin and faecal output were measured daily and xylose absorption was studied before and after each infection. A close correlation was found between a rise in plasma enteroglucagon and neurotensin and infection with enteropathogenic viruses. The three enteropathogenic viruses caused increased daily faecal output, and elevated plasma levels of enteroglucagon and neurotensin, while the non-enteropathogens did not. The calici-like virus and rotavirus but not the coronavirus caused xylose malabsorption. 相似文献
53.
54.
E. J. Hall 《The Journal of small animal practice》1990,31(11):574-579
Two dogs developed a generalised bleeding disorder after ingestion of brodifacoum, a compound belonging to a new generation of more potent and longer-acting anticoagulant rodenti-cides. Haemorrhage recurred after treatment with conventional dosages of vitamin K1 Successful therapy required dosages of vitamin K1 of 5 mg/kg for a period of up to eight weeks. 相似文献
55.
Detection of Eperythrozoon suis DNA from swine blood by whole organism DNA hybridizations 总被引:10,自引:0,他引:10
A procedure is described for isolating Eperythrozoon suis DNA of sufficient quantity and purity to serve as a probe in whole-organism DNA hybridizations for detecting parasitized swine. The E. suis organisms were isolated from the blood of infected swine; the DNA was recovered and digested with restriction endonucleases and resolved on agarose gels. In DNA hybridizations using recovered E. suis DNA, blood samples from parasitized swine could be differentiated from uninfected, control samples. A high salt lysate recovery technique was used in sampling swine whole blood for E. suis DNA and found to offer many advantages in the collection and recovery process. 相似文献
56.
An anonymous, self-administered questionnaire has been used in two independent surveys to try to determine the prevalence of scrapie in the national sheep flock. The disease was recorded in 35 counties in England and Wales. About a third (26.5 and 37.3 percent) of respondents owning 100 or more sheep indicated that they had seen sheep with scrapie in their flocks. The incidences of clinical cases recorded in affected flocks in the two surveys were 0.5 and 1.1 cases/100 ewes/year. At present there is no control over the disposal of these animals. If as has been suggested, an increase in the prevalence of scrapie was a contributory factor in the emergence of bovine spongiform encephalopathy, it would seem logical that measures should be introduced to monitor the prevalence and incidence of scrapie and to control the disposal of clinical cases. 相似文献
57.
58.
59.
60.
Dysentery lasting 4-8 days was produced in five 4-day-old colostrum-fed calves, after inoculation with an atypical strain of Escherichia coli S102-9; peak excretion of S102-9 occurred during the period of dysentery. Two calves were killed when clinical signs were most severe and bacteria were seen attached to the surfaces of enterocytes in the large intestine; microscopic lesions were seen in these areas. The lesions were identical to those previously reported in a natural outbreak of dysentery in calves, from which E. coli S102-9 was isolated, and to those seen in gnotobiotic calves experimentally infected with S102-9. Reinfection of the three surviving calves 16-20 days later with S102-9 and primary infection of two calves aged 24 and 51 days did not cause dysentery. Four of 659 coliforms isolated from field outbreaks of calf diarrhoea resembled the atypical strain S102-9. These four isolates and S102-9 did not produce heat-stable enterotoxin, but all produced a toxin cytopathic for Vero and HeLa cells. Two of the four isolates were inoculated alone into 4-day-old gnotobiotic calves deprived of colostrum; neither calf developed dysentery but microscopic lesions identical to those produced by S102-9 were detected in the large intestines of both animals. 相似文献