Perhaps you should try some spelling variations:
hanh tai » thanh tai, hang tai, han tai
nang dau » hang dau, xang dau, nang du
sach kem » hanh kem
tai cua » thai cua, tai cuc, tri cua
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, cua triet
dau hoi » cau hoi, dai hoi, dan hoi
sach ty » sach y, sach tu, sach thu
va cam » va cham, va cac, va cao
luc va » duc va, tuc va, loc va
ve cam » ve cham, ve cac, ve cai

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