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   10篇
  免费   1篇
  国内免费   1篇
林业   1篇
  1篇
综合类   2篇
农作物   1篇
畜牧兽医   6篇
园艺   1篇
  2021年   1篇
  2015年   1篇
  2011年   2篇
  2010年   1篇
  2008年   3篇
  2005年   1篇
  2003年   1篇
  1999年   1篇
  1991年   1篇
排序方式: 共有12条查询结果,搜索用时 31 毫秒
1.
The Golfe du Lion is mainly bordered by low and narrow sand dunes. Since about four decades, 1/3 of its shoreline has been receding, while 1/3 has been prograding and another 1/3 is stable. Several types of dunes may be described mainly depending on storms, high wind frequencies and sand grain size. Vegetation on dune system is distributed along a primary gradient according to sand stability and soil development, and a secondary gradient along slope of dune according to a seasonal cycle of fresh and salt phreatic water level.Global changes in climate may influence these geomorphological and biological structures mainly through:- Winter minimum temperatures changing the distribution of several plant species, especially in the middle part of the Golfe du Lion.- Frequent high storms which cause damages to the front of the dune systems and disrupt the shore. Changes in dune ecosystems will be cyclic so these tendencies will be obvious only upon a long term period.  相似文献   
2.
我国犬瘟热病毒的生态学调查研究   总被引:25,自引:0,他引:25  
本研究应用电子显微镜技术检查了17个毛皮动物和野生动物的676份材料,从犬,貂,貉,狐熊,小熊猫,大熊猫,狼,狮,虎,猞狮、金猫等12种动物病料中,检出含有CDV材料487份。应用间接ELISA、免疫荧光和中和试验等技术检测了8种动物158份血清,其中从犬,狐,小熊猫、虎、金猫,狼等6种动物的106份血清中检出了抗CDV抗体。应用RT-PCR和基因探针检查了4种动物的37份材料,其中有29份阳性。  相似文献   
3.
In West and Central Africa large carnivores have become increasingly rare as a consequence of rapid habitat destruction and lack of resources for protected area management. The Bénoué Complex (23,394 km2) in northern Cameroon is a regionally critical area for large mammal conservation. In the complex lions (Panthera leo), leopards (Panthera pardus) and spotted hyenas (Crocuta crocuta) are formally protected in three national parks and 28 hunting zones. Over-hunting may be having a strong additive effect precipitating declines in large carnivore numbers across the complex. We used a coarse level track index method to estimate the relative abundance of these three species both in hunting zones and national parks. The results were interpreted with respect to ungulate abundance, and hunting impact. There was no significant difference between the densities of medium to larger species of ungulates in the hunting zones and the national parks, and no difference in leopard and spotted hyena densities in the respective areas. However, lions occurred at significantly lower densities in the hunting zones, and even in the national parks occurred at significantly lower densities than prey biomass would predict.  相似文献   
4.
产蛋性能低和育种进展缓慢是制约狮头鹅产业发展的主要问题,研发母鹅个体产蛋量智能记录系统可实施精准选育,提高母鹅产蛋量。基于RFID(Radio frequency identification,RFID)技术,利用915 MHz非接触式无线超高频芯片和EPC Class 1 Gen 2(ISO 18000-6C)超高频读写器,设计射频接收系统及嵌入式微控制器,接收和分析母鹅ID卡信息,并结合传感器对母鹅产蛋前后体重进行检测并实时分析,判断母鹅产蛋情况;通过无线传输,将数据实时保持于迷你SQL2000数据库。结果表明:基于无线射频技术研发的狮头鹅个体产蛋智能记录系统,能较完整地记录群养母鹅个体产蛋信息,判断高产鹅、低产鹅和就巢鹅。综上,基于RFID技术的狮头鹅个体产蛋智能记录系统具有电子化、精确化、实时化、低成本的特点,在实际生产中会带来巨大的经济效益。  相似文献   
5.
采用三维定点高速摄像机对北狮“高台180°飞跃直接站腿”动作进行200帧/s频率的拍摄。首先,用视讯系统进行分段解析,得出腾空阶段中狮尾不同环节、不同时间的三维空间数据;然后,对数据应用Q-TOOLS、EXCEL等软件进行解析、计算;最后,根据计算结果分析狮尾在腾空阶段运动的运动学特征。  相似文献   
6.
Serum samples from 73 lion tamarins of three species living at the Centro de Primatologia do Rio de Janeiro were tested for antibodies against serovars of Leptospira interrogans by microscopic agglutination test. Antibodies were detected in serum samples of 15% of tested samples. Seroreactivity prevalence was lower than that described in other non-human primates and could be explained by the arboreal behaviour of these animals. Icterohaemorrhagiae was the most common serogroup.  相似文献   
7.
An 18-year-old female lion (Panthera leo) was referred to the Department of Animal Pathology of the University of Turin (Italy). At necropsy, multiple nodular, 4-20-mm, confluent white firm nodules were scattered throughout the pleural surfaces of the thoracic wall and of the lungs. Histological lesions were represented by proliferations of papillary structures lined by cuboidal basophilic mesothelial cells with large, oval nuclei and abundant granular eosinophilic cytoplasm. Immunohistochemistry revealed immunoreactivity for pancytokeratin and vimentin. None of the cells expressed calretinin antigen. Asbestos fibers and asbestos bodies were not detected respectively by light microscopy and by Scanning Electron Microscope-Energy Dispersive Spectrometer investigations. On the contrary, chrysotile asbestos were identified in samples from shelter material. Histological and immunohistochemical findings were consistent with the diagnosis of an epithelial malignant mesothelioma. To our best knowledge, this is the first report of a pleural mesothelioma in a lion.  相似文献   
8.
刘丹  齐实  王惠  麦方代  王岁权 《安徽农业科学》2010,38(5):2690-2693,2706
介绍了国内外景观环境影响评价方法的研究现状及进展。针对丽江狮子山项目整治工程的特点,对其提出了景观影响评价的评价原则及研究方法,并在项目区内,选取两个典型视点和一个典型保护区,分别进行景观影响评价,在这个过程中说明了叠图法、对比评价法和整体视觉要素评价法在景观影响评价中的应用。  相似文献   
9.
California sea lions have been a repeated subject of investigation for early life toxicity, which has been documented to occur with increasing frequency from late February through mid-May in association with organochlorine (PCB and DDT) poisoning and infectious disease in the 1970’s and domoic acid poisoning in the last decade. The mass early life mortality events result from the concentrated breeding grounds and synchronization of reproduction over a 28 day post partum estrus cycle and 11 month in utero phase. This physiological synchronization is triggered by a decreasing photoperiod of 11.48 h/day that occurs approximately 90 days after conception at the major California breeding grounds. The photoperiod trigger activates implantation of embryos to proceed with development for the next 242 days until birth. Embryonic diapause is a selectable trait thought to optimize timing for food utilization and male migratory patterns; yet from the toxicological perspective presented here also serves to synchronize developmental toxicity of pulsed environmental events such as domoic acid poisoning. Research studies in laboratory animals have defined age-dependent neurotoxic effects during development and windows of susceptibility to domoic acid exposure. This review will evaluate experimental domoic acid neurotoxicity in developing rodents and, aided by comparative allometric projections, will analyze potential prenatal toxicity and exposure susceptibility in the California sea lion. This analysis should provide a useful tool to forecast fetal toxicity and understand the impact of fetal toxicity on adult disease of the California sea lion.  相似文献   
10.
狮头鹅产蛋性状遗传性能分析   总被引:1,自引:0,他引:1  
在保持原有品种特征的基础上,改善狮头鹅繁殖力低的缺点,一直是狮头鹅本品种选育的重要内容,而对产蛋量性状的选育是其中的一个重要方面。运用现代动物遗传育种学和生物统计学,对狮头鹅产蛋量性状的遗传进行初步分析,为狮头鹅产蛋量性状的选育提供理论参考依据。随机抽取狮头鹅个体育种群中的9个家系的资料作为研究分析材料,采用同胞相关法估测狮头鹅产蛋量的遗传力,得到其结果为0.6;进而用F检验法对估测出遗传力进行检验,达到5%的显著水平;并用SSR法对各家系的产蛋平均数的差异显著性进行多重比较,结果存在相对高产和低产家系,家系1、7、5、3、9、8、2与家系6相比,以及家系1、7与家系4相比,都达到1%的差异显著水平,而家系5、3、9、8、2与家系4相比,达到5%的差异显著水平。  相似文献   
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