Perhaps you should try some spelling variations:
hien sang » hien trang, khien bang, chieu sang
tranh ban » trinh ban, tranh hang, tranh luan
dung cong » dung trong
tan thanh » tran thanh, tang thanh, toan thanh
thanh cac » hanh cac, thanh bac, thanh ca
tranh ap » tranh chap, tranh cac, tranh cai
cong tan » cong tac, cong san, cong thanh

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc hien sang - hanh ((tranh ap) or (tranh ban)) dung cong tan thanh cac~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hien sang - hanh ((tranh ap) OR (tranh ban)) dung cong tan thanh cac*.