Perhaps you should try some spelling variations:
trung tuan » trung thanh, trung tam, truong thanh
duong cong » dung cong, luong cong, duong trong
hieu lang » chieu sang, hieu quang, nhieu tang
tran tuan » tran xuan, tran quang, tran thanh
cong tan » cong tac, cong san, cong thanh
toan cao » toan tap
toan ban » van ban
ho hieu » ho chieu, hoi hieu, nho hieu

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

• Performing a fuzzy search may retrieve terms with similar spellings: ho hieu lang - hanh ((trung tuan) or (tran tuan)) duong cong tan ((toan cao) OR (toan ban))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ho hieu lang - hanh ((trung tuan) OR (tran tuan)) duong cong tan ((toan cao) OR (toan ban)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "ho hieu lang - hanh ((trung tuan) or (tran tuan)) duong cong tan ((toan cao) OR (toan ban))".
• Adding a wildcard symbol may retrieve word variants: ho hieu lang - hanh ((trung tuan) or (tran tuan)) duong cong tan ((toan cao) OR (toan ban))*.