共查询到20条相似文献,搜索用时 93 毫秒
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白羽肉鸡和黄鸡肉鸡是我国肉鸡产业的两大支柱。黄羽肉鸡是具有中国特色的肉鸡产业。经过多年的快速发展,我国黄羽肉鸡产业已经形成区域优势明显、产业特点突出、市场份额不断扩大、市场竞争力日益增强的产业。目前,我国年出栏黄羽肉鸡约40亿只,占全国鸡肉总产量的30%以上。 相似文献
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中国肉鸡产业发展历程及趋势 总被引:2,自引:0,他引:2
文章回顾了自1961年(有FAO统计数据)以来的中国肉鸡产业发展历程,系统总结了现阶段肉鸡生产的主要特点。并对未来发展趋势作出初步判断和展望。 相似文献
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"Where" and "what" in vision 总被引:3,自引:0,他引:3
The mixture of a few horizontal and vertical line segments embedded in an aggregate of diagonal line segments can be rapidly counted and their positions rapidly determined by a parallel (preattentive) process. However, the discrimination between horizontal and vertical orientation (that is, discrimination of a single conspicuous feature) requires serial search by focal attention. Under recent theories of attention, focal attention has been assumed to be required for the recognition of different combinations of features. According to the findings of this experiment, knowing "what" even a single feature is requires time-consuming search by focal attention. Only knowing "where" a target it is mediated by a parallel process. 相似文献
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高校图书馆"服务"与"爱" 总被引:1,自引:0,他引:1
张云珍 《农业图书情报学刊》2005,17(3):65-66,130
从图书馆的服务工作角度阐述了服务是一种爱的栽体,应将爱融入服务工作之中;强调了全球信息化的今天,图书管理员应丰富自己的知识,提高自己的能力,将爱落实到实处。 相似文献
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GOTTLIEB G 《Science (New York, N.Y.)》1963,139(3554):497-498
Much laboratory research is based on the assumption that the learning of parental characteristics by young nidifugous birds is rooted on visual factors. Naturalistic observations of ground- and hole-nesting duck species, augmented by sound amplification equipment, indicate that hatchlings are exposed to the call of their mother for a relatively long period before they are exposed to the sight of her. 相似文献
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庞培蓓 《信阳农业高等专科学校学报》2007,17(2):153-154
人们关注的中心为“图”,背景的部分为“底”,“图形”与“基底”的关系指一个封闭的式样与另一个和它同质的非封闭的背景之间的关系。图底关系理论在城市建筑设计中大有可为。 相似文献