全文获取类型
收费全文 | 479篇 |
免费 | 62篇 |
专业分类
林业 | 69篇 |
农学 | 15篇 |
基础科学 | 2篇 |
33篇 | |
综合类 | 78篇 |
农作物 | 10篇 |
水产渔业 | 5篇 |
畜牧兽医 | 313篇 |
园艺 | 6篇 |
植物保护 | 10篇 |
出版年
2019年 | 4篇 |
2018年 | 7篇 |
2017年 | 7篇 |
2016年 | 6篇 |
2015年 | 10篇 |
2014年 | 6篇 |
2013年 | 26篇 |
2012年 | 18篇 |
2011年 | 19篇 |
2010年 | 10篇 |
2009年 | 20篇 |
2008年 | 12篇 |
2007年 | 8篇 |
2006年 | 14篇 |
2005年 | 11篇 |
2004年 | 19篇 |
2003年 | 12篇 |
2002年 | 10篇 |
2001年 | 15篇 |
2000年 | 19篇 |
1999年 | 16篇 |
1998年 | 14篇 |
1997年 | 6篇 |
1996年 | 12篇 |
1995年 | 8篇 |
1994年 | 9篇 |
1993年 | 11篇 |
1992年 | 17篇 |
1991年 | 9篇 |
1990年 | 29篇 |
1989年 | 22篇 |
1988年 | 17篇 |
1987年 | 11篇 |
1986年 | 12篇 |
1985年 | 13篇 |
1984年 | 6篇 |
1983年 | 5篇 |
1982年 | 10篇 |
1981年 | 8篇 |
1979年 | 4篇 |
1975年 | 4篇 |
1974年 | 2篇 |
1971年 | 3篇 |
1970年 | 2篇 |
1969年 | 2篇 |
1967年 | 2篇 |
1963年 | 2篇 |
1936年 | 2篇 |
1935年 | 2篇 |
1934年 | 4篇 |
排序方式: 共有541条查询结果,搜索用时 15 毫秒
91.
92.
93.
Studies on the epidemiology of Dictyocaulus viviparus infections in Denmark have suggested that the adult lungworms present in calves around the sixth week after turnout play an important role in determining the subsequent pattern of disease. This trial was designed to test whether prophylactic treatment at this time would control disease in calves kept under British conditions. Thirty autumn-born Friesian or Friesian-cross bull calves were allowed to graze the whole of a 5 hectare field for six weeks after turnout. The field was then divided into two and the calves split into matching groups, one group being put into each of the paddocks. One group was treated with levamisole at this time and again two weeks later while the other was kept as an untreated control. Anthelmintic treatment resulted in a marked reduction in larval excretion and considerably delayed the build-up of infection on pasture. This in turn delayed the onset and reduced the severity of clinical signs in the treated group. However, as disease was not eliminated completely this prophylactic programme cannot be recommended to the British farmer in its present form. These findings are discussed in the context of the yet incomplete knowledge of the epidemiology of parasitic bronchitis. 相似文献
94.
Malignant histiocytosis in four dogs 总被引:1,自引:0,他引:1
M L Wellman D J Davenport D Morton R M Jacobs 《Journal of the American Veterinary Medical Association》1985,187(9):919-921
The clinical and pathologic features of 4 dogs with malignant histiocytosis were evaluated. The most common clinical signs were weight loss, lethargy, lymphadenopathy, hepatosplenomegaly, and anemia. Neoplastic histiocytic infiltrates most commonly were found in the spleen, bone marrow, liver, or lymph nodes. Malignant histiocytosis was considered as a differential diagnosis for anemic dogs with lymphadenopathy and/or hepatosplenomegaly. 相似文献
95.
96.
97.
Importance of Staphylococcus hyicus ssp hyicus as a cause of arthritis in pigs up to 12 weeks of age
Lame pigs, up to 12 weeks of age, were necropsied to establish a diagnosis. Of 175 pigs examined, 165 were confirmed to have arthritis by histopathological examination of joint tissues. Lesions were most common in the elbow and tarsal joints and least common in the joints of the feet. Typically, there was severe fibrinopurulent inflammation of synovial membranes regardless of the bacteria isolated. A bacterial aetiology was found in 114 (69%) of the 165 pigs. In arthritic pigs in which an aetiology was established the causative agents were Staphylococcus hyicus ssp hyicus (24.6%), Streptococcus equisimilis (26.3%), Actinomyces pyogenes (13.2%), Staphylococcus aureus (7.9%) and Haemophilus parasuis (7.9%). While gender did not affect the prevalence of arthritis, there was an age influence, most of the pigs culled for arthritis being under 6 weeks of age. 相似文献
98.
A significant decline (P = 0.047) in serum antiprotease concentration was detected in dogs with experimentally induced acute pancreatitis. Decreased serum antiprotease concentrations, similar in magnitude to those documented in the experimental dogs, were present in dogs with spontaneous, acute pancreatitis. These findings suggest that significant amounts of proteolytic enzymes escape into the systemic circulation during acute pancreatitis in dogs. These circulating enzymes may be involved in the extrapancreatic complications of acute pancreatitis. 相似文献
99.
100.
G Jacobs J Barsanti K Prasse B Selcer 《Journal of the American Veterinary Medical Association》1988,192(12):1748-1750
A urethral filling defect in the proximal portion of the pelvic urethra, suggestive of a mass, was detected by positive-contrast retrograde urethrography in 2 dogs with prostatic disease and Sertoli cell neoplasms. Extension of prostatic neoplasia into the urethra or primary urethral neoplasia were considered as explanations for the radiographic finding of an intraluminal filling defect in the pelvic urethra. Masses were visualized and biopsied during prostatic surgery. Masses were nonneoplastic and represented enlargement of the colliculus seminalis. 相似文献