分级开发 meaning in Chinese

stage development

Discussion on classification development in qinling vacation zone
秦岭北坡旅游度假带的分级开发研究
Conomic analysis model . this model has mainly four peculiarities as follows : 1 . he method of large systems resolution , assemble and gradational development is used , therefore , the dimensions of the calculation program is reduced
本模型系统主要包括了以下三个部分： 1 、支流及非控制区模拟模型2 、干流模拟模型3 、经济评价模型本模型系统主要具有以下特点： 1 、采用了大系统分解、集成、分层次开发的方法，对支流和干流模型分级开发，减小了计算模型的规模。