Perhaps you should try some spelling variations:
qua cham » qua hai, qua cac, va cham
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
duc ban » duc tan, duc van, duc man
dua ban » dia ban, cua ban, qua ban
cua tre » cua te, cuu tre, cua triet
anh do » anh doc, anh d, anh co
do cua » doi cua, co cua, de cua
x hoi » o hoi, x ho, 5 hoi

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ky nang ((x hoi) OR (xa hoi)). hieu qua cham ((duc ban) or (dua ban)) anh do cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang ((x hoi) OR (xa hoi)). hieu qua cham ((duc ban) OR (dua ban)) anh do cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky nang ((x hoi) OR (xa hoi)). hieu qua cham ((duc ban) or (dua ban)) anh do cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach ky nang ((x hoi) OR (xa hoi)). hieu qua cham ((duc ban) or (dua ban)) anh do cua tre*.