排序方式： 共有7条查询结果，搜索用时 18 毫秒
1
1.
2.
3.
通过文献考证，收集整理了浙江省古代铜矿和银矿开采和冶炼的相关记载，探讨了其资源和环境意义，为古代矿产资源信息的开发和利用（如：新的超积累植物和矿产资源的发现，消除由于古代冶炼引起的潜在的环境风险）提供了参考。 相似文献
4.
加强实验教学,培养学生综合素质和创新能力 总被引：21，自引：10，他引：21
本文以大学生素质教育的内涵为切入点，阐述了实验教学在大学生素质教育中的重要地位和作用；提出了加强实验教学的具体措施和对策，对进一步推进实验教学改革，培养大学生综合素质创新能力均具有积极的指导意义。 相似文献
5.
通过硝酸盐与硫酸亚铁、钙离子与草酸铵的反应，完善矿质肥料定性鉴定体系，改善实验的准确性，对提高实验教学质量也是十分有意义的。 相似文献
6.
Lead concentrations in roots, stems and leaves of accumulating and non-accumulating ecotypes of Sedum alfredii (Hance) were studied through a hydroponic experiment with different Pb concentrations supplied as Pb(NO3)2. Lead concentrations in leaves and stems of the accumulating ecotype were 4-9 times and 3-5 times those of the non-accumulating ecotype, and Pb-accumulated amounts in stems and leaves of the accumulating ecotype were 4-9 times and 8-11 times higher than those of the non-accumulating ecotype, respectively. The results indicated that the accumulating ecotype had better ability to transport Pb from roots to shoots. The subcellular distributions of Pb in the root, stem and leaf tissues were studied using sucrose differential centrifugation. Approximately 50% of Pb contents was found to be associated with the cell wall fraction in stems of the accumulating ecotype and the percentage increased to 80% both in roots and leaves, no matter when plants were grown with different levels of Pb. The results indicated that the distribution of Pb on cell walls of the accumulating ecotype could mainly account for the high tolerance to Pb. 相似文献
7.
INTRODUCTIONLead (Pb)existsinmanyformsinnaturalsourcesthroughouttheworld ,andisnowoneofthemostwidelyandevenlydistributedtracemet als (Nriagu ,1 992 ) .Soilandplantscanbecon taminatedbyPbfrompaints,gasolineadditives,Pbsmeltingandrefining ,pesticideproducti… 相似文献
1