Perhaps you should try some spelling variations:
sach thue » sach thu, sach thieu, sach tham
cac duc » cac du, cao duc, cac dac
hai cua » thai cua, dai cua, hoi cua
lai cua » dai cua, lai chau, thai cua
va hanh » van hanh, va thanh, va danh
hieu ve » hieu va, hieu van
sach tu » sach thu, cach tu, sach ty
cao hoi » cau hoi, co hoi, cao hoc
ve cac » va cac, vien cac

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu ((sach tu) or (sach thue)) nang cao hoi. hieu ve cac duc va hanh ((lai cua) or (hai cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach tu) OR (sach thue)) nang cao hoi. hieu ve cac duc va hanh ((lai cua) OR (hai cua)) tre.
• Adding a wildcard symbol may retrieve word variants: tu ((sach tu) or (sach thue)) nang cao hoi. hieu ve cac duc va hanh ((lai cua) or (hai cua)) tre*.