Perhaps you should try some spelling variations:
chieu tinh » trieu tinh, lieu tinh, chau tinh
hieu lang » chieu sang, hieu quang, nhieu tang
dang cong » dung cong
lua dang » cua dang, lua sang, luan nang
cong tac » cong ty
thi lua » thi luan, thi dua, thi cua
tac phi » tac thi, tac phu, tac pham
phi phi » chi phi, phi thi, thi phi

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

• Performing a fuzzy search may retrieve terms with similar spellings: doi ((hieu lang) or (chieu tinh)) - hoang thi lua dang cong tac phi phi~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doi ((hieu lang) OR (chieu tinh)) - hoang thi lua dang cong tac phi phi.
• Adding a wildcard symbol may retrieve word variants: doi ((hieu lang) or (chieu tinh)) - hoang thi lua dang cong tac phi phi*.