Perhaps you should try some spelling variations:
hanh dai » hanh tai, hanh dao, vanh dai
sach thu » sach thue, sach thieu, sach tham
hang cau » hang dau, hang ca, nhung cau
su triet » su tien, ve triet
sach thi » sach tai, sach thieu, sach tham
su viet » so viet
va hanh » van hanh, va thanh, ban hanh
truc va » thuc va, thuc vat, trung va
hieu ca » hieu cac, hieu cua, hieu va
ca cau » cua cau, cac cau, can cau

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 thi) or (sach thu)) hang cau hoi. hieu ca cau truc va hanh dai ((su triet) or (su viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach thi) OR (sach thu)) hang cau hoi. hieu ca cau truc va hanh dai ((su triet) OR (su viet)).
• Adding a wildcard symbol may retrieve word variants: tu ((sach thi) or (sach thu)) hang cau hoi. hieu ca cau truc va hanh dai ((su triet) or (su viet))*.