Perhaps you should try some spelling variations:
nang dau » hang dau, xang dau, nang du
sach kem » hanh kem
tai cua » thai cua, tai cuc, tri cua
han tai » hang tai, nhan tai, van tai
cac luc » cau luc, coc luc, cac nuoc
hieu ve » hieu va, hieu van
dau hoi » cau hoi, dai hoi, dan hoi
sach ty » sach y, sach thu, xach tay
sach tu » sach thu, cach tu, sach uu
cua tre » cua te, cuu tre, cua triet
ve cac » va cac, vien cac
luc va » duc va, tuc va, loc va
va han » va phan, van han, va hanh

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: su ((sach kem) OR (((sach tu) OR (sach ty)))) nang dau hoi. hieu ve cac luc va han tai cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach kem) or (((sach tu) OR (sach ty)))) nang dau hoi. hieu ve cac luc va han tai cua tre~".
• Adding a wildcard symbol may retrieve word variants: su ((sach kem) or (((sach tu) OR (sach ty)))) nang dau hoi. hieu ve cac luc va han tai cua tre*.