Perhaps you should try some spelling variations:
toc sach » hoc sach, thuoc sach, nuoc sach
doc sach » hoc sach, nuoc sach, dac sac
va triet » va thiet, va trien, ve triet
nang ma » tang ma, sang ma, nang cao
hieu va » lieu va, hieu qua
va pham » van pham, va phat, va phap
va hanh » van hanh, va thanh, va danh
ma hoi » mai hoi, xa hoi, ma hoa
cua tu » cua tuc, cua su, cua cu

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) OR (doc sach)) ky nang ma hoi. hieu va pham duc va hanh vi ((cua tu) OR (va triet))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) OR (doc sach)) ky nang ma hoi. hieu va pham duc va hanh vi ((cua tu) or (va triet))~".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) OR (doc sach)) ky nang ma hoi. hieu va pham duc va hanh vi ((cua tu) or (va triet))*.