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本试验研究了皖西白鹅呼吸器官的形态特征.试验选用成年皖西白鹅20只,通过颈动脉放血致死后,用10%福尔马林溶液固定.采用肉眼和显微镜观察皖西白鹅呼吸器官的形态位置与结构特征.结果表明成年皖西白鹅的呼吸器官由鼻腔、喉、气管、鸣管、支气管、气囊和肺等组成. 相似文献
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本试验研究了皖西白鹅呼吸器官的形态特征。试验选用成年皖西白鹅20只，通过颈动脉放血致死后，用10%福尔马林溶液固定。采用肉眼和显微镜观察皖西白鹅呼吸器官的形态位置与结构特征。结果表明成年皖西白鹅的呼吸器官由鼻腔、喉、气管、鸣管、支气管、气囊和肺等组成。 相似文献
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皖西白鹅生产性状及繁育的研究 总被引：3，自引：0，他引：3
首先研究了皖西白鹅基本体尺,可反映出皖西白鹅的外表各部位的发育情况及体格特征;其次,主要研究了皖西白鹅的产蛋性状、产肉性状及生长速度;最后,对皖西白鹅的人工孵化各要素及步骤作了具体描述。上述研究为皖西白鹅产业化饲养奠定了基础。 相似文献
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作者对154羽成年皖西白鹅的12项生理指标和9项生化指标进行了测定,除血清葡萄糖、血清无机磷外,其余19项指标雌雄间均无显著性差异。同时证实用枕静脉窦采血法,部位易定,操作方便,采血量大。 相似文献
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皖西白鹅属中型鹅种 ,其蛋大、壳厚 ,卵黄脂肪含量高 ,传统的自然抱孵出雏率低 ,且母鹅抱孵时间长 ,影响白鹅生产发展。随着养鹅生产的发展 ,研究白鹅的机器孵化 ,摸索机械孵化的规律势在必行。 相似文献
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本试验研究了野母鸭生殖器官的形态特征。试验应用 10只成年野母鸭 ,放血致死后 ,标本用 10 %福尔马林溶液固定 ,通过肉眼和放大镜观察其生殖器官的形态特征。结果发现野母鸭生殖器官由卵巢和输卵管两部分组成。成年母鸭仅左侧发育正常 ,右侧早已退化。卵巢大小随野鸭年龄和季节有很大变化 ;输卵管分为漏斗部、蛋白分泌部、峡部、子宫部和阴道部五部分 相似文献
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变声后期学生的歌唱训练,是成年学生在歌唱中急需解决的问题。为了使这部分学生顺利度过变声后期这一关,保护好歌唱器官,重点研究了变声后期学生的特征、训练途径和训练方法,充分体现了＂以人为本＂、＂因材施教＂的教学理念,这有利于学生科学、健康、合理地用嗓,促使声乐教学事业向更科学的方向发展。 相似文献
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近年来未成年人犯罪呈上升趋势,检察机关在办理未成年人犯罪案件中应贯彻教育为主、惩罚为辅的原则,着眼于消除未成年人犯罪的原因和条件,改进工作,创新模式,努力实现由事后消极惩罚转向事前积极防范,有效控制和预防未成年人犯罪。 相似文献
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The prevalence of child sexual abuse victimization in an adult sample of Texas residents 总被引：2，自引：0，他引：2
Attempts to identify characteristics of children who have been sexually abused have generally been based on cases reported to clinics, hospitals, law enforcement and social service agencies. In this study a questionnaire was mailed to a representative sample of the adult population in Texas. Child sexual abuse was defined as sexual interaction between a child and an adult or between two minors when the perpetrator is significantly older than the victim or is in a position of power over the victim. A return rate of 53% was obtained. The surveys returned varied from previous studies of the same population in that the respondents were slightly older, more often married and from a slightly higher socioeconomic level. They were, however, closely matched on the variables of sex, race and educational level. Childhood sexual victimization was reported by 7.4% of the respondents. Female victims comprised 82% of this group. The racial/ethnic distribution of victims paralleled that of the Texas census with 77% white, 5% black, and 16% Hispanic. Victimization rates were highest for Hispanic females followed by black and white females in that order. Hispanic and black males reported the lowest victimization rates. Based on these findings, it was estimated that 821,359 adult Texas residents were sexually abused as children. These results were compared with those of other studies along with their implications for policy-making. 相似文献
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In this article, we examine the effects of classroom characteristics on the interracial friendliness of students in desegregated classrooms. We argue that social psychological processes that affect cross-race sociability are set in motion by the classroom climate, the organization of instruction, and the class racial composition. The effects of these variables on the likelihood of cross-race friendships are observed in longitudinal data from 455 students in 16 fourth- through seventh-grade desegregated classrooms. The results show that classroom characteristics associated with "status-leveling" effects operate differently for black and white students. Ability grouping influences the interracial sociability of white students more than that of blacks, while the academic status of peers affects the cross-race friendships of blacks more than of whites. Race differences in the effects of classroom climate on interracial friendships are also observed. 相似文献
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试验取 1、30、15 0日龄三组健康皖西白鹅的消化管各段 ,制作组织切片 ,观察雏鹅、仔鹅和成体鹅的食管、腺胃、小肠各段、盲肠、直肠及卵黄囊憩室管壁内淋巴组织分布特点。见各段粘膜及粘膜下层内均存在不同类型的淋巴组织 ,其中食管、空肠、回肠、盲肠及卵黄囊憩室壁内分布的淋巴组织尤为发达 ,表明皖西白鹅消化管的局部免疫功能很强 ,其有较强的抗病力。 相似文献