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   301篇
  免费   6篇
  国内免费   2篇
林业   3篇
农学   2篇
  24篇
综合类   34篇
农作物   28篇
水产渔业   23篇
畜牧兽医   154篇
植物保护   41篇
  2021年   3篇
  2018年   4篇
  2014年   4篇
  2010年   5篇
  2009年   5篇
  2008年   2篇
  2007年   5篇
  2006年   5篇
  2005年   2篇
  2003年   2篇
  2002年   2篇
  1998年   3篇
  1997年   6篇
  1996年   7篇
  1995年   5篇
  1994年   6篇
  1993年   4篇
  1992年   6篇
  1991年   9篇
  1990年   5篇
  1989年   8篇
  1988年   6篇
  1987年   6篇
  1986年   11篇
  1985年   13篇
  1984年   5篇
  1983年   5篇
  1982年   9篇
  1981年   15篇
  1980年   8篇
  1979年   10篇
  1978年   6篇
  1977年   4篇
  1976年   5篇
  1975年   6篇
  1973年   4篇
  1972年   3篇
  1970年   4篇
  1968年   3篇
  1963年   4篇
  1959年   3篇
  1958年   9篇
  1957年   9篇
  1956年   5篇
  1955年   6篇
  1954年   7篇
  1953年   9篇
  1950年   4篇
  1948年   3篇
  1946年   2篇
排序方式: 共有309条查询结果,搜索用时 15 毫秒
71.
72.
The purpose of this study was to compare computed tomography (CT) and radiography for diagnosing the presence and severity of middle ear disease in dogs with a history of chronic otitis externa. Thirty-one dogs undergoing a total ear canal ablation and bulla osteotomy were studied. Three normal dogs served as controls. All dogs were examined using radiography and CT. Three radiologists independently evaluated imaging studies in random order. A visual analog scale method was used for scoring certainty and severity of middle ear disease. Surgical findings were recorded intra-operatively. Bulla lining samples were submitted for histopathologic evaluation and scored by a single pathologist who also used a visual analog scale system. Findings from both imaging modalities agreed more closely with surgical findings than with histopathologic findings. With either surgical or histopathologic findings as the gold standard, CT was more sensitive than and as specific as radiographs for predicting presence and severity of middle ear disease. Observer performance with CT was more consistent than the performance with radiographs in the detection of changes that occur with middle ear disease. Both radiography and CT were more accurate for predicting the severity of the disease than its presence. Findings indicate that CT is more accurate and reliable than radiography in diagnosing middle ear disease for dogs having concurrent otitis externa, but only when severity of disease is moderate or high. With low severity of disease, diagnostic certainty for both modalities becomes more variable.  相似文献   
73.
The mean packed cell volume (PCV) for canine blood samples received by post was significantly higher than that for fresh samples, at each haemoglobin value over the range 9 to 19 g/dl. As a consequence the mean corpuscular volume (MCV) and the mean corpuscular haemoglobin concentration (MCHC) also differed. Apart from one Hb value there was no significant difference in the mean red blood cell (rbc) count over the Hb range 6 to 14 g/dl. It is suggested that the normal values for the PCV and MCV should be 3 to 5% and 5 to 7 f 1 higher respectively for postal samples as compared to fresh samples while the MCHC should be about 3 to 4 g/dl lower.  相似文献   
74.
75.
76.
Our intent was to evaluate clinically total hip arthroplasty in the dog using the same procedures and prostheses. We replaced 20 hips in 15 dogs of both sexes and various breeds, weights, and ages. All animals exhibited pain caused by degenerative joint disease of one or both coxofemoral joints. Using Amstutz's system of grading at a minimum of 12 months post-operatively, none of the hips replaced were graded poor, 12.5% were graded fair, 12.5% good, and 75% excellent. Loosening of prosthetic components was by far the most common problem encountered in this study. Luxations were virtually eliminated by the use of the Richards Canine II total hip replacement system. Infections were found to be directly proportional to surgery time, number of operations performed, or both. Component failure occurred only when the size of the prosthesis was not properly matched to the size of the dog. Although these problems still must be overcome, we conclude that total hip arthroplasty is a valuable adjunct to veterinary medicine in selected cases.  相似文献   
77.
78.
79.
80.
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