Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
nang ma » tang ma, sang ma, nang cao
hieu va » lieu va, hieu qua
ma hoi » mai hoi, xa hoi, ma hoa
va cao » va cac, va co, va dao
xuc va » tuc va, luc va, xac va
cua te » cua tu
thiet » thieu

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