Perhaps you should try some spelling variations:
trong dong » trong cong, trong nong, trong dang
hoc thieu » toc thieu, hoc hien
trung cua » truong cua, trung tuan, dung cua
trung cap » truong cao, trung tam
ho chieu » theo chieu, doi chieu, mot chieu
dong tac » cong tac, dong tai, dong bac
tac than » tac thanh, tam than, tac nhan
than cap » khan cap, thanh lap, thanh cac

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: ((ho chieu) OR (hoc thieu)) xanh - thanh ((trung cua) OR (trung cap)) trong dong tac than cap~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((ho chieu) OR (hoc thieu)) xanh - thanh ((trung cua) or (trung cap)) trong dong tac than cap~".
• Adding a wildcard symbol may retrieve word variants: ((ho chieu) OR (hoc thieu)) xanh - thanh ((trung cua) or (trung cap)) trong dong tac than cap*.