Perhaps you should try some spelling variations:
hieu xanh » chieu xanh, hieu manh, hieu nganh
hung cong » nhung cong, hung cuong, phung cong
doc hieu » toc thieu, hoc thieu, hoc hien
cam hung » cac chung, cam nang, van hung
cong tap » cuong tap, cong tac, cong tan
tap toan » tap doan, tap quan, bai toan
toan ban » van 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 xanh - ((thanh tung) or (thanh cong)) cam hung cong tap toan ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu xanh - ((thanh tung) OR (thanh cong)) cam hung cong tap toan ban*.