全文获取类型
收费全文 | 351篇 |
免费 | 36篇 |
国内免费 | 2篇 |
专业分类
林业 | 27篇 |
农学 | 5篇 |
基础科学 | 2篇 |
15篇 | |
综合类 | 93篇 |
农作物 | 5篇 |
水产渔业 | 13篇 |
畜牧兽医 | 207篇 |
园艺 | 6篇 |
植物保护 | 16篇 |
出版年
2022年 | 4篇 |
2018年 | 3篇 |
2016年 | 4篇 |
2015年 | 4篇 |
2014年 | 4篇 |
2013年 | 7篇 |
2012年 | 16篇 |
2011年 | 16篇 |
2010年 | 6篇 |
2009年 | 10篇 |
2008年 | 5篇 |
2007年 | 11篇 |
2006年 | 12篇 |
2005年 | 6篇 |
2004年 | 7篇 |
2003年 | 8篇 |
2002年 | 6篇 |
2001年 | 15篇 |
2000年 | 7篇 |
1999年 | 7篇 |
1998年 | 4篇 |
1997年 | 4篇 |
1994年 | 4篇 |
1992年 | 10篇 |
1991年 | 10篇 |
1990年 | 11篇 |
1989年 | 5篇 |
1988年 | 5篇 |
1987年 | 8篇 |
1986年 | 4篇 |
1985年 | 10篇 |
1984年 | 6篇 |
1983年 | 4篇 |
1980年 | 5篇 |
1979年 | 6篇 |
1978年 | 5篇 |
1977年 | 6篇 |
1976年 | 6篇 |
1975年 | 7篇 |
1974年 | 5篇 |
1973年 | 11篇 |
1972年 | 11篇 |
1971年 | 7篇 |
1970年 | 4篇 |
1969年 | 5篇 |
1968年 | 5篇 |
1967年 | 4篇 |
1962年 | 4篇 |
1893年 | 5篇 |
1892年 | 5篇 |
排序方式: 共有389条查询结果,搜索用时 46 毫秒
1.
JS Munday H Bentall D Aberdein M Navarro FA Uzal S Brown 《New Zealand veterinary journal》2020,68(4):242-246
ABSTRACTCase history and clinical findings: A flock of 20 sheep was kept within three paddocks on a single property. None of the animals in the flock had been vaccinated against any disease for at least three years. Abdominal bloating and haemorrhagic diarrhoea were observed in Lamb 1 at 24 hours-of-age. The lamb subsequently died within an hour of the onset of clinical signs. Lamb 2 was 3-days-old when observed to be recumbent with opisthotonus. The lamb was treated with dextrose, vitamins B1 and B12, and penicillin G, but died 4 hours later.Pathological findings: Examination of Lamb 1 revealed markedly increased gas within the peritoneum and within dilated loops of intestine. The intestines were dark red and contained large quantities of haemorrhagic fluid. Histology of the intestines revealed peracute mucosal necrosis with minimal accompanying inflammation. The intestinal lumen contained cell debris, haemorrhage, and myriad large Gram-positive bacilli. The intestines of Lamb 2 did not appear bloated or reddened. However, multiple fibrin clots were visible within the pericardial sac. Histopathological examination revealed small foci of necrosis within the mucosa of the distal intestine. The necrotic foci were often associated with large numbers of large Gram-positive bacilli.Immunohistochemsitry and molecular biology: Intestinal samples from Lamb 1 were processed for Clostridium perfringens immunohistochemistry, which revealed large numbers of intralesional, positively immunostained rods. Fragments corresponding to the expected sizes for genes encoding alpha, beta, and epsilon C. perfringens typing toxins were amplified by PCR from DNA extracted from formalin-fixed sections of intestine.Diagnosis: Lamb dysentery due to C. perfringens type B.Clinical relevance: C. perfringens bacteria have a worldwide distribution, but disease due to C. perfringens type B has only been diagnosed in a small number of countries and has never been reported in New Zealand or Australia. C. perfringens type B produce both beta toxin and epsilon toxins, therefore both haemorrhagic enteritis and systemic vascular damage can develop. As many animals are exposed to C. perfringens without developing disease, there must be additional unknown factors that resulted in disease in these particular sheep. Vaccines that specifically protect against C. perfringens type B are available and may be recommended for use in smaller non-commercial flocks, as in the present case. 相似文献
2.
Landscape Ecology - The response of rare species to human land use is poorly known because rarity is difficult to study; however, it is also important because rare species compose most of... 相似文献
3.
4.
5.
6.
The pattern of decay developing in Ulmns procera killed by Ceratocystis ulmi was examined. Flammulina velutipes had caused some decay and discolouration in most trees which had been dead for more than two years. Decay caused by Pleurotus sapidus was less common. Pleurotus palmatus was frequently isolated from wood in the upper trunk showing no visible deterioration. Trees should be felled within two years of death in order to retain the value of their timber. 相似文献
7.
8.
9.
机电设备安装运行的异常现象及对策 总被引:1,自引:0,他引:1
目前,由于国产设备的技术水平和加工水平,与国外的技术设备有较大的差距,关键设备大多引进国外技术设备,其整体及配件价格十分昂贵.为了提高企业经济效益,这就要求机电设备维护人员对设备的一些异常现象,做到分析原因提出解决对策,降低设备故障减少设备维修费用. 相似文献
10.