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国家教育部积极推进大学英语教学改革，提出利用多媒体网络技术，建立以学生为中心的新型教学模式。文中介绍了西北农林科技大学英语多媒体网络教学改革试点的具体操作过程、课程内容与学时安排。总结了多媒体网络教学实践效果，并对教学过程中出现的问题和对策进行了讨论。实践表明：多媒体网络教学模式不仅有利于提高教学效率，而且有利于提高学生应用语言的能力和自主学习的能力。 相似文献
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用多媒体技术制作的数学课件在教学过程中的应用,能使复杂的问题变得直观、易懂,能使抽象的概念、定理变得具体、形象,在数学教学中采用适当的多媒体课件演示相比传统教学手段具有很多的优势,但在课件的具体应用中仍存在一些问题。本文对在教学中制作多媒体CAI数学课件遇到的问题进行了探讨。 相似文献
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随着现代教育技术的发展,多媒体辅助教学已成为目前教学的重要技术手段之一。在本文中笔者结合自己的实际工作经验,向读者介绍了笔者对多媒体辅助教学的理解,对多媒体辅助教学的现状和使用效果进行了相应的反思,并对如何更好地运用多媒体辅助教学提出笔者的几点见解,阐明了随着多媒体技术的发展,多媒体辅助教学在教学应用当中将日益显现出其重要的地位。 相似文献
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多媒体技术在《生物统计学》教学中的应用 总被引：2，自引：0，他引：2
结合<生物统计学>的课程特点,分析了多媒体技术在该课程教学中应用的必要性、优势及存在的不足,并探讨了多媒体技术在教学过程中的合理应用,以期提高<生物统计学>的教学效果. 相似文献
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野生黄鼬消化管组织结构的观察 总被引：1，自引：1，他引：0
通过组织学观察,探讨野生黄鼬消化管的组织结构特点.将8只野生黄鼬经乙醚麻醉后处死,解剖取食管、胃、小肠、大肠,制作石蜡切片,观察其组织结构.结果显示野生黄鼬食管的黏膜为复层扁平上皮,食管腺发达,肌层以骨骼肌为主.胃贲门部有发达的皱襞和贲门腺;胃底腺有大量的主细胞和壁细胞;胃大弯部的腺体以壁细胞为主,仅有少量主细胞;胃幽门部有发达的幽门腺和大量壁细胞.十二指肠黏膜层有小肠腺,内有潘氏细胞存在,黏膜下层含有十二指肠腺;空肠可见孤立淋巴小结、弥散淋巴组织及集合淋巴小结.结肠无皱襞和肠绒毛,大肠腺排列紧密,其中杯状细胞特别多;直肠固有膜内有发达的大肠腺.所以野生黄鼬消化管的特点是胃各部胃腺发达,壁细胞特别多. 相似文献
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苜蓿侧根发生与内源激素的变化 总被引：3，自引：0，他引：3
研究根系发育能力不同的苜蓿品种在主根受伤后内源激素的变化。结果表明,主根伤害后,根组织生长素含量上升,根系发育能力越强者,增加量越大。细胞分裂素(玉米素、异戊烯基腺嘌呤、双亲玉米素)和赤霉素在处理后1周时下降,随后逐渐回升。生长素/细胞分裂素、生长素/赤霉素和生长素/脱落酸的比值在处理后1周时明显增加,随后逐渐下降。叶片和根组织激素分布不一致,其中叶片生长素含量相对较高,根组织细胞分裂素含量相对较高。伤害主根后1周时,叶片细胞分裂素和生长素含量明显下降,随后逐渐回升,根系发育能力越强者恢复正常含量越快。 相似文献
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2007年4月至2008年7月,对崇明陈家镇示范绿地两栖类进行调查,根据两栖类资源和生境的特点,选取了17处调查地点。共记录到泽蛙、中华蟾蜍、黑斑蛙、金线蛙等两栖类4种,共计546只,其中泽蛙329只,占总数的61%,优势明显。在不同栖息生境中浅滩观测到两栖类种类最多,4种两栖类都观测到,在林带观测到的两栖类有266只,占总数的49%,数量最多,不同生境两栖类分布差异显著。不同水域中沟浜分布的两栖类有4种,达到全部观测4种记录,同时沟浜观测到两栖类303只,占总数的55%,数量最多,两栖类分布受水域性质影响显著。 相似文献
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为探讨喹乙醇急性中毒雏鸡血液生化指标的变化情况,。将200只5日龄伊莎公鸡雏随机分为2组,对照组饲喂基础饲粮,试验组饲喂基础饲粮+150mg/kg喹乙醇。在染毒后5、10、15d,对相关血液生化指标进行检测。结果表明,喹乙醇中毒时,在各时间点,试验组血清K+含量均高于对照组,在15d差异显著(P<0.05);试验组血清中Ca2+、PO43-、Na+含量均低于对照组,在15d差异均显著(P<0.05);试验组血清ALB、TP含量均低于对照组,ALB在15d差异显著(P<0.05),TP在10d和15d差异显著(P<0.05);试验组血清ALP、GOT、GPT活性高于对照组,GOT、GPT在15d差异显著(P<0.05)。结果显示喹乙醇中毒能够引起雏鸡相关血液生化指标的改变,喹乙醇有一定的蓄积毒性。 相似文献
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本试验旨在研究两种绿头鸭（白羽绿头鸭和绿头鸭）肌肉营养组成和价值,为绿头鸭肉产品的开发利用提供基础数据和理论依据。选择白羽绿头鸭和绿头鸭60只（每个品种各30只,公母各半）,依照国家标准测定胸肌粗蛋白质、粗脂肪、胆固醇含量及氨基酸、脂肪酸、微量元素和维生素的组成和含量,并对胸肌进行氨基酸评价及脂肪酸营养价值评价。结果显示,白羽绿头鸭肌肉粗蛋白质含量显著低于绿头鸭（P<0.05）;两种绿头鸭肌肉中均检测到17种含量大于0.01%的氨基酸,其中白羽绿头鸭肌肉苏氨酸、组氨酸、丝氨酸和脯氨酸含量显著高于绿头鸭（P<0.05）,赖氨酸、谷氨酸和精氨酸含量显著低于绿头鸭（P<0.05）;检测到13种含量均大于0.01%的脂肪酸,其中白羽绿头鸭硬脂酸和油酸含量显著低于绿头鸭（P<0.05）;检测到9种矿物质元素（钠、镁、钾、钙、锰、铁、铜、锌和硒）,两种绿头鸭差异不显著（P>0.05）;检测到8种维生素,白羽绿头鸭肌肉维生素B1含量显著高于绿头鸭（P<0.05）,维生素D和维生素E含量显著低于绿头鸭（P<0.05）。两种绿头鸭肌肉氨基酸比例接近世卫组织推荐的理想模式,富含人体所需的矿物质元素和维生素,具有广阔的开发利用前景。 相似文献
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Marioni-Henry K Vite CH Newton AL Van Winkle TJ 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2004,18(6):851-858
A retrospective review of records of 205 cats with histologically confirmed disease of the spinal cord was performed to identify the prevalence of disease in this nonrandomly selected population of cats. Clinical records were reviewed, and age, duration of neurologic illness, and clinical and histopathologic findings in cats with spinal cord disease were abstracted. Disease processes were classified into 7 categories and 23 groups. The most common diseases affecting the spinal cord of cats were feline infectious peritonitis (FIP), lymphosarcoma (LSA), and neoplasia of the vertebral column secondarily affecting the spinal cord. Information on age, onset and duration of clinical signs, and lesion localization at the postmortem examination in cats belonging to the 7 categories of disease were analyzed to create a practical list of differential diagnoses. Cats were also subcategorized into 3 groups based on their age at death. FIP was the most common disease of cats younger than 2 years of age. LSA and vertebral column neoplasia were the most common diseases affecting cats between 2 and 8 years of age. Vertebral column neoplasia was the most common disease affecting cats older than 8 years of age. Results of this histopathologic study showed that FIP and LSA were the most common disease processes affecting the spinal cord of cats. However, at least 21 other groups of diseases and their relative prevalence were identified. 相似文献
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This experiment was aimed to study the nutritional content and value of the muscles of two mallards (White feather mallard and mallard),and provide basic data and theoretical basis for the development and utilization of mallard meat products.60 White feathered mallards and mallards (30 for each breed,half of male and female) were chosen,and the composition and content of pectoral muscle crude protein,crude fat,cholesterol,amino acids,fatty acids,trace elements and vitamins were determined according to national standards and the nutritional values of muscle were evaluated.The results showed that the content of crude protein in muscle of White feather mallard was significantly lower than that of mallard (P<0.05).17 kinds of amino acids with contents higher than 0.01% were detected in the muscles of the two kinds of mallards,among which the contents of threonine,histidine,serine and proline in the muscles of the White feather mallard were significantly higher than those of mallard (P<0.05).The contents of lysine,glutamate and arginine were significantly lower than those of mallard (P<0.05).13 kinds of fatty acids with contents higher than 0.01% were detected,and the contents of stearic acid and oleic acid were significantly lower than those of the mallard.9 mineral elements (sodium,magnesium,potassium,calcium,manganese,iron,copper,zinc and selenium) in two kinds of mallards were detected,and there was no significant difference between the two kinds of mallards (P>0.05).8 kinds of vitamins were detected,and the content of vitamin B1 in muscle of White feather mallard was significantly higher than that of mallard (P<0.05),but the contents of vitamin D and vitamin E were significantly lower than that of mallard (P<0.05).The ratio of amino acids in muscle of two kinds of mallards was close to the ideal model recommended by WHO,which was rich in mineral elements and vitamins for human body,and had a broad prospect of development and utilization. 相似文献
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OBJECTIVE: To characterise 18 isolates of Haemophilus paragallinarum isolated from chickens in Indonesia. PROCEDURE: The isolates were identified to species level by traditional phenotypic methods. Six of the isolates were also identified by a species-specific polymerase chain reaction. Fourteen of the isolates were examined for resistance to a panel of seven antimicrobial agents using a disc diffusion method. All 18 isolates were serotyped according to the Page scheme using reference antisera in a haemagglutination inhibition test. RESULTS: Four of the 18 isolates were obtained from indigenous (kampung) chickens, with the remainder being from typical intensive poultry production systems. The 18 isolates were obtained from 11 outbreaks that showed the typical clinical signs of infectious coryza and 11 of the isolates were obtained from chickens that had been vaccinated with infectious coryza vaccines. All 18 isolates were confirmed as H paragallinarum by biochemical testing and six isolates were also identified as H paragallinarum by the polymerase chain reaction test. Eleven isolates were resistant to erythromycin and streptomycin, 10 to neomycin, eight to oxytetracycline, five isolates to doxycycline, three to sulphamethoxazoltrimethoprim but only one to ampicillin. Seven isolates were Page serovar A, four were Page serovar B and seven were Page serovar C. CONCLUSION: The presence of all three Page serovars (A, B and C) has been confirmed for the first time in Indonesian chickens. As the majority of the infectious coryza vaccines in use in Indonesia contain only serovar A and C, the presence of serovar B in chickens indicates that the protection by these bivalent vaccines would be reduced. The use of trivalent infectious coryza vaccines that contain serovars A, B and C is recommended for use in Indonesia. 相似文献
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鸭胰腺内高血糖素—,胰岛素—和生长抑素—免疫反应细胞的形态及分布 总被引：1，自引：0，他引：1
用ABC免疫组织化学方法,对1 周龄绍鸭胰腺内的高血糖素(A)、胰岛素(B)和生长抑素(D)免疫反应细胞的形态及分布进行了观察。结果表明,上述3 种细胞在全胰的分布及形态有差异。A 细胞主要成群散在于A 胰岛,少数位于混合型胰岛的边缘。D 细胞主要散在于A 胰岛中,少数位于B胰岛和混合型胰岛的边缘。B细胞主要呈团块状分布于B胰岛,少数位于混合型胰岛的中央。在胰外分泌部有散在的A 和D 细胞,位于腺泡及导管上皮细胞之间或结缔组织中。A 细胞形态各异,以多边形为主,多数细胞伸出形态多样的胞质突起,伸达胰岛或其他细胞间。D细胞的形态与A 细胞相似。B细胞形态均一,呈圆形或卵圆形,未见胞质突起,在外分泌部未见到B细胞。 相似文献
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基于非靶向代谢组学技术,分析腹腔注射苦参碱前后昆明小鼠粪便和血浆代谢物的差异,并通过与此前16S rDNA测序结果联合分析探究苦参碱发挥药理作用的可能机理。将20只昆明小鼠随机分为2组,分别是苦参碱处理组(MT)和生理盐水处理组(NC)。苦参碱处理组每天腹腔注射40 mg·kg-1的苦参碱,连续给药5 d,每天给药2次。生理盐水处理组按照同样方式和体积腹腔注射生理盐水。给药第6天,分别收集各组小鼠的粪便和血浆,进行非靶向代谢组学检测,并与苦参碱处理组肠道菌群的16S rDNA测序结果进行联合分析。苦参碱处理组的粪便及血浆中均存在显著差异代谢物,粪便中共鉴定出97种,血浆中有44种。聚类分析显示,粪便中苦参碱组有35种代谢物上调,104种代谢物下调;血浆中苦参碱组有20种代谢物上调,35种代谢物下调。KEGG通路分析显示粪便及血浆差异代谢物被映射到Protein digestion and absorption等代谢途径。与16S rDNA测序分析得到的显著差异菌种嗜酸乳杆菌关联分析,结果表明粪便及血浆代谢物与嗜酸乳杆菌存在相关性。苦参碱可调节昆明小鼠的体内代谢,在粪便和血浆中均存在显著差异代谢物。这些差异代谢物及与菌群之间的互作可能是其发挥药理作用的关键。 相似文献