Perhaps you should try some spelling variations:
hanh tai » thanh tai, hang tai, han tai
su sach » so sach, vu sach
tai cua » thai cua, tai cuc, tri cua
truc va » thuc va, thuc vat, trung va
cua tre » cua te, cuu tre, cua triet
hieu ve » hieu va, hieu van
dai hai » dai han, dai hoi, dai tai
sach v » sach va, sach y, sach 2
tuc va » thuc va, tuc xa, duc va
v nang » va nang, vu nang, van nang
ve cac » va cac, vien cac

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 v nang ((cau hoi) or (dai hai)). hieu ve cac ((tuc va) OR (truc va)) hanh tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach v nang ((cau hoi) OR (dai hai)). hieu ve cac ((tuc va) OR (truc va)) hanh tai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach v nang ((cau hoi) or (dai hai)). hieu ve cac ((tuc va) OR (truc va)) hanh tai cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach v nang ((cau hoi) or (dai hai)). hieu ve cac ((tuc va) OR (truc va)) hanh tai cua tre*.