Perhaps you should try some spelling variations:
hieu van » thien van, lieu va, hieu ve
ban hang » ngan hang
tu sach » thu sach, su sach, te sach
vai cua » dai cua, hai cua, lai cua
cua tre » cua te, cuu tre, cua triet
cam duc » cam xuc, cao duc, pham duc
sach ky » sac ky, sach y, sach ty
hieu va » lieu va, hieu qua
lang xa » lang ha, dang xay, lang van
ky lang » ky nang, ky dang, ky tang

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ky lang xa hoi. ((hieu van) or (hieu va)) cam duc ((ban hanh) OR (ban hang)) vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky lang xa hoi. ((hieu van) OR (hieu va)) cam duc ((ban hanh) OR (ban hang)) vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky lang xa hoi. ((hieu van) or (hieu va)) cam duc ((ban hanh) OR (ban hang)) vai cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ky lang xa hoi. ((hieu van) or (hieu va)) cam duc ((ban hanh) OR (ban hang)) vai cua tre*.