Perhaps you should try some spelling variations:
hieu hieu » hien hieu, hieu hien, thien hieu
hieu cac » hieu luc, hieu va, hieu van
thu sach » tu sach, thuat sach, thuoc sach
cua viet » ca viet, hoa viet, cua vat
tang ma » mang may, tang van
nang ma » sang ma, nang cao, mang may
sach ty » sach y, sach tu, sach thu
hanh di » hanh vi, hanh de, hang di
loc va » hoc va, luc va
di cua » dai cua, doi cua, de cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach ty ((nang ma) OR (tang ma)) hoi. hieu hieu cac ((duc va) or (loc va)) hanh di cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ty ((nang ma) OR (tang ma)) hoi. hieu hieu cac ((duc va) OR (loc va)) hanh di cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ty ((nang ma) OR (tang ma)) hoi. hieu hieu cac ((duc va) or (loc va)) hanh di cua viet".
• Adding a wildcard symbol may retrieve word variants: thu sach ty ((nang ma) OR (tang ma)) hoi. hieu hieu cac ((duc va) or (loc va)) hanh di cua viet*.