全文获取类型
收费全文 | 544篇 |
免费 | 57篇 |
专业分类
林业 | 15篇 |
农学 | 2篇 |
41篇 | |
综合类 | 84篇 |
农作物 | 15篇 |
水产渔业 | 29篇 |
畜牧兽医 | 388篇 |
园艺 | 15篇 |
植物保护 | 12篇 |
出版年
2021年 | 5篇 |
2020年 | 11篇 |
2019年 | 7篇 |
2018年 | 5篇 |
2017年 | 14篇 |
2016年 | 7篇 |
2015年 | 13篇 |
2014年 | 16篇 |
2013年 | 22篇 |
2012年 | 22篇 |
2011年 | 18篇 |
2010年 | 9篇 |
2009年 | 11篇 |
2008年 | 25篇 |
2007年 | 22篇 |
2006年 | 22篇 |
2005年 | 18篇 |
2004年 | 27篇 |
2003年 | 28篇 |
2002年 | 16篇 |
2001年 | 10篇 |
2000年 | 12篇 |
1999年 | 20篇 |
1998年 | 20篇 |
1997年 | 16篇 |
1996年 | 11篇 |
1995年 | 8篇 |
1994年 | 12篇 |
1993年 | 10篇 |
1992年 | 7篇 |
1991年 | 5篇 |
1990年 | 5篇 |
1989年 | 14篇 |
1988年 | 8篇 |
1987年 | 7篇 |
1986年 | 5篇 |
1985年 | 5篇 |
1984年 | 5篇 |
1981年 | 6篇 |
1980年 | 7篇 |
1979年 | 4篇 |
1974年 | 7篇 |
1972年 | 4篇 |
1971年 | 6篇 |
1970年 | 5篇 |
1969年 | 6篇 |
1968年 | 4篇 |
1967年 | 5篇 |
1966年 | 6篇 |
1960年 | 4篇 |
排序方式: 共有601条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
5.
6.
7.
8.
J. Fraser McConnell BVM&S Laurent S. Garosi DVM 《Veterinary radiology & ultrasound》2004,45(4):327-330
Intervertebral disk extrusion is rarely reported in the cat. In this case, the clinical, radiologic, and magnetic resonance imaging findings of an acute intramedullary intervertebral disk extrusion in a 5-year-old domestic shorthaired cat are described. Radiographically, there was mineralized disk material within the vertebral canal. On magnetic resonance images, the disk material was found to be within the spinal cord. A linear disk trail extending from the disk space into the spinal cord may be specific for intramedullary disk extrusion. 相似文献
9.
P Zhang N Fegan I Fraser P Duffy R E Bowles A Gordon P J Ketterer W Shinwari P J Blackall 《Journal of veterinary diagnostic investigation》2004,16(5):458-460
Two outbreaks of fowl cholera on a multiage free-range egg farm were investigated. The outbreaks occurred in 1994 and 2002. A total of 22 strains of Pasteurella multocida were available for study, 11 from the 1994 outbreak and 11 from the 2002 outbreak. Lesions typical of acute fowl cholera were seen in the 1994 outbreak, whereas both acute and chronic fowl cholera occurred in the 2002 outbreak. The isolates were examined in an extended phenotypic typing methodology, by a P. multocida-specific polymerase chain reaction (PCR), by the Heddleston somatic serotyping scheme, and by restriction endonuclease analysis (REA) typing using the enzyme HpaII. All 22 strains had the same phenotypic properties, all were confirmed as P. multocida by PCR, all were Heddleston serovar 4, and all had the same REA pattern. The results indicate that these 2 outbreaks were caused by the same clone of P. multocida--despite the 8-year time period between the outbreaks. 相似文献
10.
Infrared spectroscopy and nitrogen analyses suggest that secondary amide groups in protein-like components of soil clay-organic complexes and extracted organic matter decompose above 100°C to yield ammonia which is retained as NH4+ by acid-washed clay-organic complexes. Above about 400°C, other volatile nitrogenous decomposition products are released. Clay surfaces in the clay-organic complexes may catalyse the decomposition. 相似文献