排序方式： 共有3条查询结果，搜索用时 93 毫秒
1
1.
Among the numerous inland river basins in the arid northwest China, Shiyang River basin is known for its most serious water shortage that constrains its social and economic developments and for some of the worst eco-logical and environmental deterioration in China. The research on the value of water resources used for ecosystem is the basis for reasonable allocation of water resources between users of ecosystem and economic system. In this paper the concept of dynamic value for the ecosystem services is proposed. A modified coefficient for the ecosys-tem service value per unit area is proposed according to the cover degrees of biomes combined with expert consul-tation. Based on the developmental stage coefficient and scarcity of ecological resources, a dynamic evaluation method is proposed. The theoretical formula and simple calculation formula of the sharing benefits coefficient and benefits per unit ecological water utilization are proposed. The result shows that the benefit of unit ecological water utilization in the lower reach was greater than that in the upper reach in the Shiyang River basin. 相似文献
2.
随着信息化、网络化时代的到来，开展有效的校本教研活动，建构新型的、高效的校本教研模式是目前中小学急需探究的问题。近年来我校对信息技术环境下的校本教研模式进行了认真研究和反复尝试，建构了模式的雏形，并多次开展了验证性校本教研活动，取得了卓有成效的研究成果，本文就模式建构的理论和实践进行阐述。 相似文献
3.
1