Perhaps you should try some spelling variations:
dang xay » dang van, van xay
ban hanh » ban hang
hieu ve » hieu va, hieu van
cac hoc » cach hoc, cac hop, bac hoc
hoc ban » hoc bang, hoc dan, hoc bai
hanh di » hanh vi, hanh de, hang di
te sac » te sach, te cac, te san
sac ky » cac ky, sai ky
ve cac » va cac, vien cac
di cua » dai cua, doi cua, de cua
cua te » cua tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sac ky ((mang may) or (dang xay)) hoi. hieu ve cac hoc ban hanh di cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sac ky ((mang may) OR (dang xay)) hoi. hieu ve cac hoc ban hanh di cua te.
• Adding a wildcard symbol may retrieve word variants: te sac ky ((mang may) or (dang xay)) hoi. hieu ve cac hoc ban hanh di cua te*.