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《中国现代教育装备》2004,(8):68-68
据相关资料显示：我国是近视眼的患病大国，1995年有3亿人患有近视眼，占世界近视眼病人的33％。其中病理性近视眼超过200万人。近年来近视眼的发生率越来越高，上海、北京等大中城市近视率可达50％-60％，在医学院校。近视率甚至高达70％-80％，小学3，4年级的近视率也达到30％-40％。最近的一份调查显示：我国小学生的近视发病率为22．78％，中学生为55．22％，而大学生高达76.74％。近视已经成为困扰中国学生的严重问题。 相似文献
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何家涛 《襄樊职业技术学院学报》2006,5(2):8-9
以非洲萄幼嫩花托为外植体，以MS为基本培养基，添加不同浓度6．BA、IBA、GA等进行愈伤组织诱导、不定芽分化、照代增殖、生根培养和过渡炼苗。试验表明：采用MS＋6-BA2．0-5．0mg/L（单住下同）＋IBA0．25-0．5培养基，愈伤诱导率在60％以上；采用MS＋6-BA4．0＋IBA0．25＋GA0．5-2．0培养基对不定芽的生长度增殖效果好。增殖率可达13．5；采用1／2MS＋NAA0．1或IBA0．1-0．5或IAA0．5-1．0培养基，20d生根率达100％；在蛭石：珍珠岩：泥炭=1：1：1基质中驯苗。成活率可达95％以上。 相似文献
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两种芦荟属（Aloe L．）植物花粉活性和柱头可授性的测定 总被引：5，自引：0，他引：5
文章采用TTC法和醋酸洋红染色法测定皂质芦荟[Aloe saponaric(Ait．)HaW．]和元江芦荟(Aloe yuanjiangensis Xiong，Zheng et Liu)的花粉活力。用TTC法测定的结果表明：皂质芦荟花粉的平均可育率为65．48％，元江芦荟花粉的平均可育率为52．28％醋酸洋红染色法测定的结果为：皂质芦荟花粉的平均可育率为64．02％，元江芦荟花粉的平均可育率为55．46％。用联苯胺-过氧化氢法测定柱头可授性的结果表明，二者的柱头均具较高的可授性。 相似文献
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高职低年级学生补考率高的原因与对策 总被引：2，自引：0，他引：2
一、高职学生存在低年级补考率高的现象当前，高职院校普遍存在学生考试补考的现象，且比率呈低年级高、高年级低的状况。以我院航海系学生为例：９７级学生中，一年级时补考率达５．５％，二年级时补考率达４．１％；９８级学生中，一年级时补考率达１０．４％，二年级时补考率达７．６％；９９级学生中，一年级时补考率达８．３％，二年级时补考率达５．６％。如下图所示：从调查中我们还发现高职学生在一年级时，其课程多为公共课和专业基础课，如高等数学、思想品德、大学英语、计算机基础、航海数学、电子学等。这些课程原来大都学过，… 相似文献
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《海外英语》2007,(5):10-11
Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help? 相似文献
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《海外英语》2007,(4):36
There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love. 相似文献
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Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject. 相似文献
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Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities. 相似文献
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RUZBEHANI Mohsen 《重庆大学学报(英文版)》2004,3(1):20-25
1.IntroductionOne-cyclecontrolmethod,whichwasproposedaboutonedecadeago[1],hasbecomeanattractivemethodinspecialfieldssuchaspowerfactorcorrection[2-6],switchingamplifiers[7,8],etc.Themainideaofthiscontrollerisbasedonintegrationofdiodevoltageinone-cycleandforcesittobeexactlyequaltothereferencevalue.Themainadvantageofthiscontrollerisitsrealtimeabilitytorejectthevariationofinputvoltage[1].Despitethisgreatability,ithasnogoodperformancesinrejectingofloaddisturbanceandfollowingreferencecommands.Espec… 相似文献
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唐芳 《读与写:教育教学刊》2008,5(6)
During interview with English majors, it was found that a majority of students expressed disappointment with their experience of English literature classes. Students' dislike of learning English literature appears to be the major problem of teaching English literature in China. Reader response approach is a good way to solve this problem. In this paper, I explain the rationale behind the reader response approach, such as its origin, definition, features, assumptions, and strategies. Then I illustrate how reader response approach works as a teaching strategy by presenting several teaching models. At last I evaluate its usefuiness for teachers and present the advantages of reader response approach in Chinese context. 相似文献