Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
hang vai » hang va, hang tai, hang hai
ban hang » ngan hang
hieu van » hieu va, thien van, lieu va
dua ban » dia ban, cua ban, qua ban
cua tre » cua te, cuu tre, dua tren
tu sach » thu sach, su sach, te sach
cau dua » cau qua, cau cua, ca dua
sach ky » sac ky, sach y, sach ty
van cau » van dau, van hau, van chat
ma hoi » mai hoi, xa hoi, me hoi

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: tu sach ky nang ((ma hoi) OR (ma hoa)). hieu van cau dua ban hang vai ((cua tre) OR (cua triet))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang ((ma hoi) or (ma hoa)). hieu van cau dua ban hang vai ((cua tre) OR (cua triet))~".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang ((ma hoi) or (ma hoa)). hieu van cau dua ban hang vai ((cua tre) OR (cua triet))*.