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小学低年级数学课前尝试性作业怎样实现高效性
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作者 王娴 《学周刊(下旬)》 2014年第9期136-136,共1页
课前尝试性作业,是教师在向学生讲授新课之前,让学生先根据自己的知识水平和生活经验所进行的尝试性学习,它不等同于课前预习。课前尝试性作业的布置要从提高学生兴趣入手,题目设计要符合学生实际,教师要对学生完成课前尝试性作业给予... 课前尝试性作业,是教师在向学生讲授新课之前,让学生先根据自己的知识水平和生活经验所进行的尝试性学习,它不等同于课前预习。课前尝试性作业的布置要从提高学生兴趣入手,题目设计要符合学生实际,教师要对学生完成课前尝试性作业给予方法指导,同时要认真做好评价。 展开更多
关键词 课前 尝试性 作业 科学布置 方法 指导 评价高效性
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Assessment of effectiveness of nature reserves on the Tibetan Plateau based on net primary production and the large sample comparison method 被引量:6
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作者 张镱锂 胡忠俊 +7 位作者 祁威 吴雪 摆万奇 李兰晖 丁明军 刘林山 王兆锋 郑度 《Journal of Geographical Sciences》 SCIE CSCD 2016年第1期27-44,共18页
Twenty-one typical coupled large samples were chosen from areas within and surrounding nature reserves on the Tibetan Plateau using the large sample comparison method(LSCM).To evaluate the effectiveness of the nature ... Twenty-one typical coupled large samples were chosen from areas within and surrounding nature reserves on the Tibetan Plateau using the large sample comparison method(LSCM).To evaluate the effectiveness of the nature reserves in protecting the ecological environment,the alpine grassland net primary production(NPP) of these coupled samples were compared and the differences between them before and after their establishment as protected areas were analyzed.The results showed that:(1) With respect to the alpine grassland NPP,the ecological and environmental conditions of most nature reserves were more fragile than those of the surrounding areas and also lower than the average values for the Tibetan Plateau.(2) Of the 11 typical nature reserves selected,the positive trend in the NPP for Manzetang was the most significant,whereas there was no obvious trend in Taxkorgan.With the exception of Selincuo,the annual NPP growth rate in the nature reserves covered by alpine meadow and wetland was higher than that in nature reserves consisting of alpine steppe and alpine desert.(3) There were notable findings in 21 typical coupled samples:(a) After the establishment of the nature reserves,the annual rate of increase in the NPP in 76% of samples inside nature reserves and 82% of samples inside national nature reserves was higher than that of the corresponding samples outside nature reserves.(b) The effectiveness of ecological protection of the Mid-Kunlun,Changshagongma,Zoige and Selincuo(Selin Co) nature reserves was significant; the effectiveness of protection was relatively sig-nificant in most parts of the Sanjiangyuan and Qiangtang nature reserves,whereas in south-east Manzetang and north Taxkorgan the protection effectiveness was not obvious.(c) The ecological protection effectiveness was significant in nature reserves consisting of alpine meadow,but was weak in nature reserves covered by alpine steppe.This study also shows that the advantage of large sample comparison method in evaluating regional ecology change.Careful design of the samples used,to ensure comparability between the samples,is crucial to the success of this LSCM. 展开更多
关键词 nature reserves protection effectiveness large sample comparison method net primary production Tibetan Plateau
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