Perhaps you should try some spelling variations:
theo hieu » theo chieu, theo tieu, thien hieu
hieu lang » chieu sang, hieu quang, nhieu tang
trinh vat » trinh van, trinh luat, sinh vat
hang cong » dang cong, hang nong, bang cong
trinh va » trinh van, trinh ve, trinh vi
cong san » cong tac
san toan » van toan, dan toan, manh toan
toan tap » toan ban

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

• Performing a fuzzy search may retrieve terms with similar spellings: theo hieu lang - hanh ((trinh va) or (trinh vat)) hang cong san toan tap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: theo hieu lang - hanh ((trinh va) OR (trinh vat)) hang cong san toan tap.
• Adding a wildcard symbol may retrieve word variants: theo hieu lang - hanh ((trinh va) or (trinh vat)) hang cong san toan tap*.