Perhaps you should try some spelling variations:
hoc thieu » toc thieu, hoc hien
canh anh » anh anh, canh tranh, thanh anh
cong san » cong tac
san toan » van toan, dan toan, manh toan
toan ban » van ban
doi chi » doi khi
va dang » van dang, va lang, da dang
va nang » van nang, da nang, cam nang

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

• If you are trying to use Boolean operators, they must be ALL CAPS: ((hoc thieu) OR (doi chi)) xanh - canh anh ((va dang) OR (va nang)) cong san toan ban~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((hoc thieu) or (doi chi)) xanh - canh anh ((va dang) OR (va nang)) cong san toan ban~".
• Adding a wildcard symbol may retrieve word variants: ((hoc thieu) or (doi chi)) xanh - canh anh ((va dang) OR (va nang)) cong san toan ban*.