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

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

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