Perhaps you should try some spelling variations:
dua tren » dung tren
hanh dai » hanh tai, hanh dao, vanh dai
va hanh » van hanh, va thanh, va danh
cac duc » cac du, cao duc, cac dac
hieu ve » hieu va, hieu van
sach ky » sac ky, sach y, sach kem
sach ty » sach y, sach tu, sach thu
ve cac » va cac, vien cac
cua te » cua tu
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: su ((sach ky) OR (sach ty)) nang x hoi. hieu ve cac duc va hanh dai ((dua tren) or (cua te))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach ky) OR (sach ty)) nang x hoi. hieu ve cac duc va hanh dai ((dua tren) OR (cua te))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach ky) OR (sach ty)) nang x hoi. hieu ve cac duc va hanh dai ((dua tren) or (cua te))*".