Perhaps you should try some spelling variations:
thanh trung » thanh tung
luong cong » dung cong, trong cong, cong cong
cong thanh » dong thanh, cong trinh, cong tan
hieu lang » chieu sang, hieu quang, nhieu tang
trung cua » truong cua, trung tuan, trung cap
cua luong » cu luong, cua huong, chat luong
doc hieu » toc thieu, hoc thieu, hoc hien
tran huu » tran duc
toan tap » toan ban

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

• Performing a fuzzy search may retrieve terms with similar spellings: doc hieu lang - thanh trung cua luong cong thanh ((tran huu) or (toan tap))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu lang - thanh trung cua luong cong thanh ((tran huu) OR (toan tap)).
• Adding a wildcard symbol may retrieve word variants: doc hieu lang - thanh trung cua luong cong thanh ((tran huu) or (toan tap))*.