Perhaps you should try some spelling variations:
hoc thiet » hoc thieu, hoc thuyet, toc thieu
hang ban » hang luan, hang va, hang tai
cua dung » cua dong, qua dung, cua rung
cua dang » cua cong, cua ban
cong dan » cong san, cong tan, huong dan
dan toan » van toan, dan than, manh toan
toan cao » toan ban, toan tap

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 thiet) OR (hoc hien)) tach - hang ban ((cua dung) OR (cua dang)) cong dan toan cao~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((hoc thiet) OR (hoc hien)) tach - hang ban ((cua dung) or (cua dang)) cong dan toan cao~".
• Adding a wildcard symbol may retrieve word variants: ((hoc thiet) OR (hoc hien)) tach - hang ban ((cua dung) or (cua dang)) cong dan toan cao*.