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   738篇
  免费   4篇
  国内免费   1篇
林业   13篇
农学   5篇
  45篇
综合类   166篇
农作物   5篇
水产渔业   11篇
畜牧兽医   455篇
植物保护   43篇
  2022年   2篇
  2019年   2篇
  2014年   4篇
  2012年   57篇
  2011年   72篇
  2010年   16篇
  2008年   66篇
  2007年   71篇
  2006年   60篇
  2005年   42篇
  2004年   46篇
  2003年   50篇
  2002年   52篇
  2001年   16篇
  2000年   37篇
  1999年   21篇
  1998年   13篇
  1997年   9篇
  1996年   5篇
  1995年   13篇
  1994年   13篇
  1993年   14篇
  1992年   3篇
  1991年   3篇
  1986年   4篇
  1984年   2篇
  1980年   2篇
  1979年   3篇
  1976年   2篇
  1975年   2篇
  1974年   1篇
  1973年   1篇
  1972年   2篇
  1971年   1篇
  1970年   3篇
  1969年   1篇
  1968年   1篇
  1967年   3篇
  1966年   2篇
  1963年   1篇
  1960年   2篇
  1959年   1篇
  1958年   1篇
  1956年   1篇
  1955年   2篇
  1953年   1篇
  1952年   2篇
  1951年   1篇
  1945年   1篇
  1929年   1篇
排序方式: 共有743条查询结果,搜索用时 0 毫秒
61.
62.
A 17-month-old cat presented for frequent swallowing, occasional cough and stertor. Radiographic evaluation revealed a soft tissue mass at the level of the soft palate. Oral examination revealed a soft tissue mass within the soft palate. Surgical resection was performed. Histopathology was consistent with a large developmental cyst. Following surgical management the cat has remained clinically free of signs for 2 months.  相似文献   
63.
Dog ownership is considered a risk factor for campylobacteriosis in humans. This study investigated the prevalence and shedding of Campylobacter spp. in kennelled dogs. Faecal samples (n=399) were collected in longitudinal studies from 52 dogs in two kennels. Campylobacter spp. were isolated using charcoal-based selective agars and direct PCR. The prevalence of Campylobacter spp. in dogs in boarding kennels ranged from 46% (95% CI 22, 72) on entry, to 50% (95% CI 30, 70) overall, and in dogs in 'rescue' kennels from 68% (95% CI 49, 84) on entry to 73% (95%, CI 56, 87) overall. C. upsaliensis was isolated from 62% (95% CI 48, 73) of the dogs, whilst C. jejuni was isolated from 15% (95% CI 7, 26) of animals. The majority of infected dogs entered the kennels already carrying Campylobacter spp., and remained infected throughout their stay. However, in some cases, shedding appeared to commence after kennelling. Given that the prevalence of C. upsaliensis and C. jejuni was relatively high in dogs from both boarding and rescue kennels, such animals may pose a zoonotic risk.  相似文献   
64.
OBJECTIVE: To examine the relationship between medial palmar intercarpal ligament (MPICL) tearing and postoperative performance in racing horses. MATERIALS AND METHODS: The postoperative performance of 42 horses in which the midcarpal joint was examined arthroscopically was followed prospectively. Intra-articular variables examined were the severity of MPICL tearing, subchondral bone damage and articular cartilage damage. Using a scoring system based on the class of race and the position in the race, a mean score was calculated for up to five races before and after surgery. The preoperative score was subtracted from the postoperative score to give a net score. Statistical analysis was by a Mann Whitney U test and multiple linear regression. RESULTS: Thirty-two (76%) raced postoperatively, 23 (55%) won at least one race and 12 of 26 (46%) performed at the same or higher level. Horses with grades 2 to 4 MPICL tearing had significantly lower net scores than those with grade 1 or no tearing. The severity of subchondral bone damage was the only variable on its own that was significantly correlated with net score (r2 = 0.23, P < 0.05). The addition of the grade of MPICL tearing to bone damage significantly improved the prediction of postoperative performance (P < 0.05). The inclusion of articular cartilage damage had no effect on the prediction of postoperative performance. CONCLUSION: Tears involving more than one third of the MPICL as observed arthroscopically have a significant detrimental affect on postoperative performance of racing horses.  相似文献   
65.
鸡传染性法氏囊病(上)   总被引:2,自引:0,他引:2  
  相似文献   
66.
猪传染性胃肠炎病毒的分子生物学研究进展刘爵(北京农业大学)猪传染性胃肠炎病毒(TGEV)可引起仔猪发生以呕吐、急性腹泻和脱水为特征的胃肠炎,该病对2周龄以内的仔猪具有高度致死性,给养猪业造成严重的损失。TGEV属于冠状病毒科冠状病毒属,呈多形性,表面...  相似文献   
67.
作者根据美国养猪业的实践,结合已有的猪病防治经验,特制订下述表格,以指导猪场疾病防治工作,现摘译如下。  相似文献   
68.
69.
A 6-year-old spayed female domestic shorthair cat was examined because of a 2-week history of rhythmic muscle movements. Physical examination revealed thoracic limb rigidity, contracture of the carpi, generalized muscle atrophy, and rhythmic rippling of the muscles of all 4 limbs. Results of a CBC and serum biochemistry profile were unremarkable other than high creatine kinase activity. Electromyography revealed unique high-frequency discharges, including rhythmic bursts of single motor unit potentials appearing as doublets (myokymia) and more prolonged bursts of nonrhythmic motor unit potentials with characteristic waning amplitudes (neuromyotonia). Histologic examination of muscle biopsy specimens revealed noninflammatory necrotizing myopathy with regeneration. The cat did not respond to treatment with carbamazepine or prednisone but improved rapidly after treatment with phenytoin was initiated. Six months after initial examination, electromyography revealed a substantial decrease in the amount of spontaneous activity in previously affected muscles. However, the myokymic and neuromyotonic discharges were still present, albeit with a substantial decrease in frequency.  相似文献   
70.
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