Perhaps you should try some spelling variations:
hieu xanh » chieu xanh, hieu manh, hieu nganh
trung cua » truong cua, trung tuan, dung cua
trung cap » truong cao, trung tam
dung cong » dung trong
doc hieu » toc thieu, hoc thieu, hoc hien
cong tac » cong ty
than cap » khan cap, thanh lap, thanh cac
phan cau » phan dau, phan cac, phan tu

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu xanh - hanh ((trung cua) OR (trung cap)) dung cong tac ((than cap) OR (phan cau))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc hieu xanh - hanh ((trung cua) OR (trung cap)) dung cong tac ((than cap) or (phan cau))~".
• Adding a wildcard symbol may retrieve word variants: doc hieu xanh - hanh ((trung cua) OR (trung cap)) dung cong tac ((than cap) or (phan cau))*.