density step灰度等级densityn.密度；浓度；比重density intergrowth matrix灰度共生矩阵density-dependent effect密度效应density-dependent growth密度依赖性生长density functional methods密度泛函方法density of freight traffic货运密度density data of population人口密度数据density and speed relation甘草稀溶液浓度density-based clustering基于密度的聚类density-dependent factor密度有关因子density of solid particles固体颗粒密度

1. Studies on Clonal Test and Spacing Effect of New Clones of Populus tomentosa Carr.
   毛白杨新无性系对比试验与造林密度效应研究。