Perhaps you should try some spelling variations:
hanh vai » hanh vi, hanh va, hanh tai
xang dau » hang dau
sach ky » sac ky, sach ty, sach kem
vai cua » dai cua, hai cua, lai cua
cua tre » cua te, cuu tre, cua triet
hieu va » lieu va, hieu qua
dau hoi » cau hoi, dai hoi, dan hoi
tuc va » thuc va, truc va, duc va
va cam » va cham, va cac, va cao

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) or (sach y)) xang dau hoi. hieu va cam ((tuc va) OR (tuc xa)) hanh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach ky) OR (sach y)) xang dau hoi. hieu va cam ((tuc va) OR (tuc xa)) hanh vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach ky) or (sach y)) xang dau hoi. hieu va cam ((tuc va) OR (tuc xa)) hanh vai cua tre".
• Adding a wildcard symbol may retrieve word variants: su ((sach ky) or (sach y)) xang dau hoi. hieu va cam ((tuc va) OR (tuc xa)) hanh vai cua tre*.