首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   243篇
  免费   13篇
林业   20篇
农学   6篇
  20篇
综合类   36篇
农作物   24篇
水产渔业   15篇
畜牧兽医   121篇
园艺   4篇
植物保护   10篇
  2022年   5篇
  2021年   3篇
  2020年   6篇
  2019年   6篇
  2018年   5篇
  2017年   2篇
  2016年   6篇
  2015年   1篇
  2014年   5篇
  2013年   23篇
  2012年   7篇
  2011年   13篇
  2010年   13篇
  2009年   13篇
  2008年   11篇
  2007年   12篇
  2006年   15篇
  2005年   8篇
  2004年   6篇
  2003年   8篇
  2002年   11篇
  2001年   4篇
  2000年   7篇
  1999年   4篇
  1998年   8篇
  1997年   13篇
  1996年   7篇
  1995年   1篇
  1994年   2篇
  1993年   2篇
  1992年   7篇
  1990年   4篇
  1989年   3篇
  1988年   2篇
  1983年   2篇
  1982年   2篇
  1981年   1篇
  1979年   1篇
  1976年   1篇
  1921年   2篇
  1916年   2篇
  1912年   2篇
排序方式: 共有256条查询结果,搜索用时 15 毫秒
91.
Severe lameness attributed to osteochondrosis is described in an extensively managed Brahman herd grazing on improved native pasture. Clinical signs were observed in five animals, three of which were necropsied. The most prominent lesions were in the elbow and stifle joints. There was multiple fissuring and ulceration of thickened articular cartilage with numerous osteochondral bodies present in the joint spaces. All affected animals were entire males sharing a common ancestral sire. Inheritance and gender were suspected to be contributing factors in the development of the disease.  相似文献   
92.
93.
94.
95.
The black‐lip pearl oyster, Pinctada margaritifera, used for round pearl production in Polynesia, is generally cultured using “ear‐hanging” where they are attached to a rope to form “chaplets.” In other countries, pearl oysters are cultured using panel (pocket) nets that are more expensive than chaplets but afford more protection to cultured oysters. Prior research has shown panel nets produce pearls of higher quality and value, potentially generating higher profits. This study used cost–benefit analysis to compare pearl production using chaplet‐based and panel net‐based culture methods. Whole farm data, including gross revenues and annual production costs, fixed and variable, were analyzed. Average production cost per pearl using panel net‐based culture was USD 22.47 and for chaplet‐based culture was USD 21.55. However, use of panel nets saved around 3,430 hr (USD 6,860) of labor a year, offsetting the greater capital investment. A chaplet‐based pearl farm generated USD 65,738 in annual profits compared to USD 88,774 for a panel net‐based farm. Positive cash flow was achieved 1 year earlier (Year 7) for the panel net‐based farm. This is the first economic analysis of different pearl culture methods for P. margaritifera and evidence of profitability will support further development of the black‐lip pearl industry in the Indo‐Pacific region.  相似文献   
96.
A 6-year-old 41.8-kg (92-lb) sexually intact male German Shepherd Dog used as an attack and pursuit dog by the local police department was examined because of general malaise and sudden onset of ataxia. Abnormal findings included a high WBC count, fever, and ongoing weight loss. Physical examination was unrevealing initially, in part because of the aggressive nature of the dog. Following treatment with antibiotics, an abdominal mass was detected during a second physical examination, and was confirmed radiographically. Subsequent ultrasound examination revealed a walled mass of mixed echogenicity, with areas of detectable fluid movement. A laparotomy was performed to remove the mass, which weighed 2.2 kg (4.5 lb). Histologic findings were consistent with botryomycosis, and Staphylococcus intermedius was isolated on bacteriologic culture. Postoperative treatment consisted of intravenous, intra-abdominal, and oral administration of antibiotics. Diagnosis of botryomycosis requires histologic examination and bacteriologic culture of the lesion. Treatment consists of surgical intervention and administration of antimicrobials. Botryomycosis is a poorly understood and rarely reported disease found in many species. A computer search of the literature failed to reveal any previous reports of intra-abdominal botryomycosis in dogs.  相似文献   
97.
98.
99.
100.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号