Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
van hanh » van thanh, ban hanh, van anh
hieu va » lieu va, hieu qua
vuc van » duc van, luc van, thuc van
cac vuc » cac nuoc, cac vung, cac cuoc
te sach » toc sach
nang ma » tang ma, sang ma, nang cao
ty nang » ky nang, ty xang, ty hang
ma hoi » mai hoi, xa hoi, ma hoa

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: ((te sach) OR (thuoc sach)) ty nang ma hoi. hieu va cac vuc van hanh vi ((cua su) OR (qua su))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) or (thuoc sach)) ty nang ma hoi. hieu va cac vuc van hanh vi ((cua su) OR (qua su))~".
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (thuoc sach)) ty nang ma hoi. hieu va cac vuc van hanh vi ((cua su) OR (qua su))*.