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
ve triet » va trien, su triet
hanh cau » nhanh cau, hang cau, hanh cac
thi hanh » thi thanh
cac tuc » cac toc, cac tu, cac nuoc
cac tac » cac toc, cac bac, cac dac
xa hanh » xa thanh, xa khanh, va hanh
vai ve » va ve, dai ve, vai 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 hanh cau hoi. hieu qua ((((cac tuc) OR (cac tac))) or (cac thoi)) xa hanh vai ve triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach thi hanh cau hoi. hieu qua ((((cac tuc) OR (cac tac))) OR (cac thoi)) xa hanh vai ve triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach thi hanh cau hoi. hieu qua ((((cac tuc) OR (cac tac))) or (cac thoi)) xa hanh vai ve triet".
• Adding a wildcard symbol may retrieve word variants: toc sach thi hanh cau hoi. hieu qua ((((cac tuc) OR (cac tac))) or (cac thoi)) xa hanh vai ve triet*.