Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hieu cua » hieu qua, dieu cua, bieu cua
va triet » va thiet, va trien, cua triet
hanh vai » hanh vi, hanh va, hanh tai
van hanh » van thanh, ban hanh, van anh
ve triet » va trien, su triet
xuc van » duc van, luc van, vuc van
nang ma » tang ma, sang ma, mang may
cac xuc » cam xuc, cac nuoc, chat xuc

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

• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach y ((nang ma) OR (nang cao)) hoi. hieu cua cac xuc van hanh vai ((va triet) OR (ve triet))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach y ((nang ma) OR (nang cao)) hoi. hieu cua cac xuc van hanh vai ((va triet) or (ve triet))~".
• Adding a wildcard symbol may retrieve word variants: toc sach y ((nang ma) OR (nang cao)) hoi. hieu cua cac xuc van hanh vai ((va triet) or (ve triet))*.