Perhaps you should try some spelling variations:
hien tinh » khien tinh, thien tinh, bien tinh
lang luan » tang luan, bang luan, lang xuan
hang luan » tang luan, dung luan
hang cong » dang cong, hang nong, bang cong
tan tranh » tan tran, can tranh, lan tranh
tranh ban » trinh ban, tranh hang, tranh luan
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 tinh - nhanh ((lang luan) or (hang luan)) hang cong tan tranh ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hien tinh - nhanh ((lang luan) OR (hang luan)) hang cong tan tranh ban*.