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   309篇
  免费   11篇
林业   9篇
农学   7篇
基础科学   1篇
  15篇
综合类   40篇
农作物   4篇
水产渔业   8篇
畜牧兽医   225篇
园艺   7篇
植物保护   4篇
  2023年   2篇
  2021年   3篇
  2020年   3篇
  2019年   4篇
  2017年   4篇
  2016年   2篇
  2015年   5篇
  2014年   3篇
  2013年   11篇
  2012年   8篇
  2011年   6篇
  2010年   10篇
  2009年   7篇
  2008年   7篇
  2007年   11篇
  2006年   7篇
  2005年   3篇
  2004年   12篇
  2003年   9篇
  2002年   10篇
  2001年   7篇
  2000年   3篇
  1999年   10篇
  1998年   19篇
  1997年   16篇
  1996年   11篇
  1995年   8篇
  1994年   12篇
  1993年   11篇
  1992年   4篇
  1991年   7篇
  1990年   8篇
  1989年   8篇
  1988年   8篇
  1987年   3篇
  1986年   5篇
  1985年   2篇
  1984年   5篇
  1982年   3篇
  1981年   3篇
  1979年   3篇
  1976年   2篇
  1975年   3篇
  1974年   2篇
  1972年   3篇
  1971年   3篇
  1970年   4篇
  1969年   3篇
  1968年   2篇
  1965年   2篇
排序方式: 共有320条查询结果,搜索用时 176 毫秒
1.
2.
3.
The diets suitable for the hand rearing of piglets in incubators were examined. Diet A was based on cows' milk heated to 56 degrees C and had bacteriostatic and antiadhesive properties against Escherichia coli. Diet B was based on evaporated cows' milk and did not have these properties. The numbers of coliform bacteria naturally colonising the small intestines of newborn piglets fed entirely on these diets for one week did not differ significantly, however both were significantly higher than in control piglets suckled from birth. Faecal counts of coliforms were similar in all three groups. Examination of the bacteriostatic sensitivity of the isolated strains to sows' milk indicated a predominance of milk-sensitive strains colonising the suckled piglets and a predominance of milk-resistant strains in the piglets fed diet B. This diet-dependent colonisation could not be explained by the in vitro bacteriostatic properties of the diets alone.  相似文献   
4.
5.
Sixty-nine intestinal spirochetes isolated from pigs and poultry in eastern Australia were selected to evaluate the effectiveness of a species-specific PCR-based restriction fragment length polymorphism (RFLP) analysis of the Brachyspira nox gene. For comparative purposes, all isolates were subjected to species-specific PCRs for the pathogenic species Brachyspira hyodysenteriae and Brachyspira pilosicoli, and selected isolates were examined further by sequence analysis of the nox and 16S ribosomal RNA genes. Modifications to the original nox-RFLP method included direct inoculation of bacterial cells into the amplification mixture and purification of the PCR product, which further optimized the nox-RFLP for use in a veterinary diagnostic laboratory, producing sufficient product for both species identification and future comparisons. Although some novel profiles that prevented definitive identification were observed, the nox-RFLP method successfully classified 45 of 51 (88%) porcine and 15 of 18 (83%) avian isolates into 5 of the 6 recognized species of Brachyspira. This protocol represents a significant improvement over conventional methods currently used in veterinary diagnostic laboratories for rapid specific identification of Brachyspira spp. isolated from both pigs and poultry.  相似文献   
6.
7.
8.
Adrenalectomies for canine adrenal tumours are associated with peri-operative morbidity and mortality. Objectives of this study included assessing the prognostic value of tumour- or surgery-related variables in predicting peri-operative mortality and overall survival in dogs undergoing adrenalectomies for primary adrenal tumours as well as pre-treatment with phenoxybenzamine on survival to discharge with pheochromocytomas specifically. A multi-institutional retrospective cohort study was performed across nine institutions. Electronic medical record searches identified 302 dogs which met the inclusion criteria. Data collected included dog-related, tumour-related, treatment-related, surgery-related, and outcome variables. Univariate and multivariable logistic regression and cox proportional hazards models were used to identify variables associated with death prior to discharge and tumour-related survival. Overall, 87% of dogs survived to discharge with a tumour-related survival time of 3.96 years. Post-operative complications were reported in 25%. Increased surgical time (p = 0.002) and pre-surgical medical treatment other than phenoxybenzamine (p = 0.024) were significantly associated with increased peri-operative mortality while ureteronephrectomy (p = 0.021), post-operative pancreatitis (p = 0.025), and post-operative aspiration pneumonia (p < 0.001) were significantly associated with decreased overall survival. Phenoxybenzamine pretreatment had no effect on peri-operative mortality. Thirty-seven of 45 (82%) dogs with pheochromocytomas not pretreated survived to discharge, and 50 of 59 (85%) dogs with pheochromocytomas pretreated with phenoxybenzamine survived to discharge (p = 0.730). This study provides information on risk factors for death prior to discharge and tumour-related survival that may help guide clinical management and owner expectations. In addition, the study findings challenge the previously reported benefit of phenoxybenzamine for pretreatment of dogs undergoing adrenalectomies for pheochromocytomas.  相似文献   
9.
10.
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