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   112篇
  免费   4篇
林业   5篇
农学   1篇
  12篇
综合类   7篇
农作物   5篇
水产渔业   9篇
畜牧兽医   59篇
植物保护   18篇
  2022年   2篇
  2021年   6篇
  2020年   1篇
  2019年   4篇
  2018年   8篇
  2017年   4篇
  2015年   7篇
  2014年   5篇
  2013年   6篇
  2012年   5篇
  2011年   9篇
  2010年   3篇
  2009年   2篇
  2008年   7篇
  2007年   7篇
  2006年   5篇
  2005年   7篇
  2004年   4篇
  2003年   7篇
  2002年   7篇
  2000年   4篇
  1998年   1篇
  1995年   1篇
  1994年   1篇
  1991年   1篇
  1990年   1篇
  1967年   1篇
排序方式: 共有116条查询结果,搜索用时 15 毫秒
51.
ABSTRACT Rosellinia necatrix mycoreovirus 3 (W370) (RnMYRV-3/W370, described as RnMYRV-3 in this paper), a member of the newly established genus Mycoreovirus within the family Reoviridae, is the hypovirulence factor of the white root rot fungus, Rosellinia necatrix. Two virus-free fungal isolates (W37 and W97) that were somatically incompatible with the virus-harboring field isolate (W370) were transfected with purified RnMYRV-3 particles. Virus infection was confirmed by electrophoresis and northern hybridization of viral double-stranded RNA. RnMYRV-3 was transmissible from transfected strains to their respective, virus-free counterparts via hyphal anastomosis. Virus-transfected strains produced smaller lesions on apple fruits than did their virus-free counterparts. Virus-cured strains were indistinguishable from wild-type strains in culture morphology and displayed approximately the same virulence level on apples. Virus-transfected strains had "mosaic" colony portions consisting of thin, fast-growing and dense, slow-growing mycelia, and grew more slowly as a whole than their virus-free, parental strains. The level of virus accumulation varied among virus-transfected subcultures and within its single colonies. Virus-transfected strains were occasionally cured, as was W370. Such a phenomenon may be ascribed to uneven viral distribution in single colonies and the difficulty in viral transmission to virus-free hyphae.  相似文献   
52.
53.
A longitudinal study was carried out to evaluate the diagnostic potential of the previously developed direct faecal real-time quantitative PCR (QPCR) assay (Kawaji et al., 2007) for the detection of Mycobacterium avium subsp. paratuberculosis (MAP) infected sheep. Of the 58 sheep, 38 were orally inoculated with MAP, while 20 controls were maintained separately from the infected group throughout the trial. All animals were tested by QPCR, faecal culture and serum ELISA pre-inoculation and at 4, 8 and 13 months post-inoculation, and were necropsied at 13 months post-inoculation. Eighteen out of 38 inoculated sheep were detected by QPCR to be shedding MAP in faeces at 4 months post-inoculation, while only one sheep was positive in faecal culture at this time point. At 8 months post-inoculation, MAP DNA was detected in faeces of all inoculated sheep by QPCR, while MAP organisms were isolated from only 34% of the inoculated animals by faecal culture. The QPCR results for faecal samples that were collected at necropsy demonstrated that faecal QPCR was more sensitive than culture of intestinal tissues for MAP. The QPCR assay was confirmed to be a sensitive and specific ante-mortem diagnostic test for MAP in sheep, circumventing faecal culture which is a less sensitive and highly time consuming test. Quantification of MAP DNA in faeces by QPCR may provide immediate information to estimate the stage of the infection as well as the risk of transmission from infected animals.  相似文献   
54.
The first chordates appear in the fossil record at the time of the Cambrian explosion, nearly 550 million years ago. The modern ascidian tadpole represents a plausible approximation to these ancestral chordates. To illuminate the origins of chordate and vertebrates, we generated a draft of the protein-coding portion of the genome of the most studied ascidian, Ciona intestinalis. The Ciona genome contains approximately 16,000 protein-coding genes, similar to the number in other invertebrates, but only half that found in vertebrates. Vertebrate gene families are typically found in simplified form in Ciona, suggesting that ascidians contain the basic ancestral complement of genes involved in cell signaling and development. The ascidian genome has also acquired a number of lineage-specific innovations, including a group of genes engaged in cellulose metabolism that are related to those in bacteria and fungi.  相似文献   
55.
Objective: To evaluate open heart surgery with deep surface‐induced hypothermia (sHT) and low‐flow cardiopulmonary bypass (CPB) in small and toy‐breed dogs. Study Design: Case series. Animals: Small breed dogs (n=8) weighing <5.5 kg with naturally occurring cardiac disease. Methods: Deep sHT under isoflurane anesthesia and low‐flow rate CPB with a small‐volume prime circuit were used. Ventricular septal defect was closed directly in 2 dogs and severe mitral regurgitation was corrected with mitral valvuloplasty (MVP) in 5 dogs and mitral valve replacement in 1 dog. Results: All dogs survived surgery; 1 dog died 6 days and 1 died 2 months after MVP. The other 6 dogs lived (mean follow‐up, 32.8 months; range, 12–65 months). Mean body weight at surgery was 3.6 kg (range, 2–5.3 kg). Mean lowest esophageal temperature was 21.4°C (range, 19.8–23.8°C). Mean lowest pump flow volume was 29.2 mL/kg/min (range, 9.4–57.7 mL/kg/min) during aortic cross‐clamping (mean, 53.5 minutes; range, 25–79 minutes). Mean hematocrit before CPB was 38.6% (range, 33–47%) and 20.3% (range, 13–24%) during CPB with a small circuit priming volume of 225–260 mL. Conclusion: Deep sHT with low‐flow rate CPB may be used for open heart surgery in small dogs weighing <5.5 kg. Clinical Relevance: Open heart surgery for selected congenital defects and acquired defects in small and toy‐breed dogs may be successfully performed using deep sHT and CPB.  相似文献   
56.
Histopathological analyses of red crown rot (RCR) of soybean were performed using field-grown and indoor-grown soybean plants. These analyses revealed that soybean plants formed a periderm to prevent pathogen invasion. When a break formed in the periderm, an additional periderm newly differentiated into the inner cells and prevented pathogen invasion. If the pathogen reached the intravascular tissues, some xylem parenchyma cells died, and the vessels were occluded by gum. Periderm formation and vessel occlusion were observed not only in slightly diseased soybean plants, but also in seriously diseased plants, indicating that both reactions function as part of the defense response against RCR.  相似文献   
57.
International Aquatic Research - In the inner area of the Sea of Ariake, rearing experiments were conducted to examine how the survival rates of juveniles of three bivalve species (Anadara...  相似文献   
58.
59.
60.
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