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经调查,珠海及周边海域已发现虾类7科15属26种,其中对虾科1属3种,占11.54%;猬虾科2属2种,占7.69%;长臂虾科6属10种,占38.46%;鼓虾科2属4种,占15.38%;蝼蛄虾科1属2种,占7.69%;龙虾科1属2种,占7.69%;虾蛄科2属3种,占11.54%,在此基础上对该海区的虾类资源作了评价,提出了资源开发保护的建议。并从养殖规模和养殖技术两方面总结了珠海主要经济虾类的养殖现状,指出了优质虾苗繁殖较困难、病害防治水平较低、产品质量较差、销售渠道狭窄等制约虾类养殖业发展的主要问题,据提出了该地区虾类养殖业发展的相应对策。 相似文献
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本文报道了新疆北疆地区水生甲虫6个科29个属53个种,其中15个中国新记录种.采集的种类中牙甲科和龙虱科的种类占绝对优势.前者有9个属23个种,占水生甲虫种类的43%,后者共有13个属18个种,占总种类的34%,其次是沟背牙甲科.仅1属5种,占总种类的9%,豉甲科3个属4个种,占总种类的8%,沼梭科2属2种,占总种类的4%,平唇水龟虫科,仅1属1种,占总种类的2%. 相似文献
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湖北省淡水溪蟹分布及地理区划研究 总被引：1，自引：0，他引：1
湖北地区已发现淡水溪蟹33种,其中东洋界的物种30种,占90.9%;古北界的物种1种,占3.0%;广布两界的物种2种,占6.1%。与邻近的贵州、湖南、江西和河南地区的淡水溪蟹区系比较研究后,湖北地区淡水溪蟹区系应划归东洋界。 相似文献
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贵州动植物资源十分丰富 ,植物类群有苔藓、菌类、蕨类、种子类。其中苔藓类 345种 ,分属5 0科 ;菌类 30 0 0种 ,其中真菌 1 93种 ,分属 2 8科 ;蕨类 680种 ,分属5 3科 ;种子类约 490 0种 ,分属 1 2 3科。其种数占全国总数的 2 0 .6% ,孑遗植物繁多 ,如银杉、铁杉、罗汉松、珙桐、喜树、鹅掌楸等等 ;植物地理成分复杂 ,热带一亚热带性质的成分优势明显 ;特有珍稀植物较多 ,据统计 ,贵州已列入国家珍稀濒危保护植物名录的植物共 67种 ,占全国的 1 8.9% ,其中一级保护植物有银杉、秃杉、珙桐、桫椤等 4种 ;二级保护植物有喙核桃、钟萼木、梵净… 相似文献
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对南蛇藤果和果壳挥发油的化学成分进行分析.采用同时蒸馏-萃取法(SDE)提取南蛇藤果和果壳挥发油,再用气相色谱-质谱法进行分析.结果表明：南蛇藤果挥发油中鉴定出25种化合物,占挥发油质量分数的98.3%,其中,醇类2种占1.78%,醛类3种占13.8%,酯类1种占4.51%,酚类1种占1.11%,烯烃类13种占65.8%,烷烃类2种占3.60%,其他类3种占7.66%;南蛇藤果壳挥发油中鉴定出21种化合物,占挥发油质量分数的98.1%,其中,醇类2种占1.65%,酯类1种占2.85%,酮类1种占0.460%,酚类1种占0.910%,烯烃类6种占77.0%,烷烃类4种占6.54%,其他类6种占8.65%.两种挥发油中含13种相同化合物,其中,南蛇藤果中衣兰烯质量分数为45.0%,南蛇藤果壳中衣兰烯质量分数为62.4%. 相似文献
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《嘉应学院学报》2020,(3):48-54
采用实地调查、文献资料等方法调查了世界客都城区蓝色花卉植物的种类、属性及其利用现状.结果表明:客都城区共有蓝色花卉植物16科、31属、35种,分别占该区域植物总数的6.9%、3.5%、1.5%.其中草本28种,占80%;灌木4种,占11.4%;草本或亚灌木1种,占2.9%;灌木或小乔木1种,占2.9%;乔木1种,占2.9%. 35种蓝色花卉植物中,野生种类11种,栽培种类17种,栽培或野生种类7种.客都城区蓝色花卉植物的4种典型花色为蓝色、深蓝色、淡蓝色和蓝紫色;唇形科、马鞭草科和菊科为客都城区蓝色花卉植物的优势科;大部分蓝色花卉植物的花期在3月～8月;客都城区蓝色花卉植物的地理区系类型以泛热带分布为主.编制的客都城区蓝色花卉植物名录,可为客都及其附近地区的植物景观设计、园林绿化提供参考与指导. 相似文献
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一、沈阳工业学院青年教师队伍的现状沈阳工业学院现有青年教师 42 1人 ,占教师总数的 61 .3 %。其中研究生以上学历 (含助教班、双学位 ) 2 78名 ,占教师总数的 40 .5 % ;副教授 49名 ,占青年教师的 1 1 .6% ,讲师 1 80名 ,占 42 .8% ;中共党员 2 37名 ,占 56 .3 %。主讲两门课以上的有2 66名 ,占青年教师总数的 63 .1 % ;在院教授督导团听课的 2 0 6名青年教师中 ,教学效果优秀人数为91名 ,占 44.1 % ,良好 97名 ,占 47.3 % ,较差 8名 ,占 3 .9%。科研方面 ,据不完全统计 ,近两年参加横项课题的有 66名 ,其中担任课题组长的有 2 9名 ;参加… 相似文献
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张掖地区蝶类的补报及垂直分布特点 总被引：1，自引：0，他引：1
2000-2002年6-9月,对祁连山北坡及河西走廊蝶类经行采集,共采集蝶类标本500余号,经鉴定、整理,隶属于8科32种.在张掖地区总共采集到蝶类8科81种,根据世界及中国昆虫地理区划,其中东洋古北共有17种,占21%,古北种64种,占79%,古北种占绝对优势.其垂直分布特点为中部走廊荒漠、绿洲地带以世界性广布种为主,2500-3200米祁连山山地森林草原带蝶类以适应于寒温带山地的中国东北亚区以及欧洲—西伯利亚亚区成份为主,海拔3200m以上的亚高山灌丛草甸带,呈现典型的、适应青藏高原高寒山地的特有成份. 相似文献
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对清水河保护区的两栖动物进行了调查,共采集标本53号,隶属1目5科9属11种,占贵州省两栖动物总数64种(亚种)的17.19%。主要区系成分为华中华南区种,共5种,占保护区总种数的45.45%;其次为西南区种4种,占保护区总种数的36.36%;华中区种仅2种,占保护区总种数的18.18%。 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