Perhaps you should try some spelling variations:
hanh tai » thanh tai, hang tai, han tai
te sach » toc sach
tai cua » thai cua, tai cuc, tri cua
sach ky » sac ky, sach y, sach ty
va tham » van tham, va cham, va thanh
hieu va » lieu va, hieu qua
dai hai » dai han, dai tai, dai thao
dai hoi » dai hoc, dai moi
ky lang » ky nang, ky dang, ky tang
cua tre » cua te, cuu tre, cua triet
lao va » tao va, cao va, bao va
lo va » lo van, ly va, le va

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sach ky lang ((dai hoi) OR (dai hai)). hieu va tham ((lo va) or (lao va)) hanh tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky lang ((dai hoi) OR (dai hai)). hieu va tham ((lo va) OR (lao va)) hanh tai cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ky lang ((dai hoi) OR (dai hai)). hieu va tham ((lo va) or (lao va)) hanh tai cua tre*".