Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
sach thi » sach thu, sach tai, sach thieu
hanh vai » hanh vi, hanh va, hanh tai
cac thoi » cac toi, cac hop, cac tro
va triet » va thiet, va trien, ve triet
hang cau » hang dau, hang ca, nhung cau
thi hang » thi hanh, thi nang, thi hong
cac tuc » cac toc, cac tac, cac nuoc
xa hanh » xa thanh, xa khanh, va hanh
cac tu » cac thu, cach tu, cac du
vai va » mai va, dai va, hai va

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach thi hang cau hoi. hieu qua ((((cac tuc) OR (cac tu))) or (cac thoi)) xa hanh vai va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach thi hang cau hoi. hieu qua ((((cac tuc) OR (cac tu))) OR (cac thoi)) xa hanh vai va triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach thi hang cau hoi. hieu qua ((((cac tuc) OR (cac tu))) or (cac thoi)) xa hanh vai va triet".
• Adding a wildcard symbol may retrieve word variants: toc sach thi hang cau hoi. hieu qua ((((cac tuc) OR (cac tu))) or (cac thoi)) xa hanh vai va triet*.