Perhaps you should try some spelling variations:
danh vai » danh sai, danh va, doanh van
vu sach » vu bach, su sach, vu khach
vai cua » dai cua, hai cua, lai cua
va danh » va dinh, va dan, va hanh
hieu de » hieu ve, hieu he, hieu le
cua tre » cua te, cuu tre, cua triet
ty hang » ly hang, ty xang, thi hang
ty nang » ky nang, ty xang, ly nang
ma hoi » mai hoi, ma hoa, me hoi
de dat » de dao
nuoc » quoc, duoc, ngoc

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: vu sach ((ty nang) OR (ty hang)) ((ma hoi) OR (xa hoi)). hieu de dat nuoc va danh vai cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu sach ((ty nang) or (ty hang)) ((ma hoi) OR (xa hoi)). hieu de dat nuoc va danh vai cua tre~".
• Adding a wildcard symbol may retrieve word variants: vu sach ((ty nang) or (ty hang)) ((ma hoi) OR (xa hoi)). hieu de dat nuoc va danh vai cua tre*.