Perhaps you should try some spelling variations:
thanh hoi » thanh hoai, thanh hoa, thanh hai
ban thanh » ban hanh, ban hang
tu sach » thu sach, su sach, te sach
cam dua » ca dua, chay dua, cach dua
hoi cua » hoi chuc
cay dua » chay dua, cay lua, ca dua
cua tre » cua te, cuu tre, cua triet
sach ty » sach y, sach tu, sach thu
hieu ve » hieu va, hieu van
dan hoi » dan hoc, dai hoi, van hoi
dau hoi » cau hoi, dai hoi, dau noi
ty nang » ky nang, ty xang, ty hang

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ty nang ((dau hoi) OR (dan hoi)). hieu ve ((cam dua) or (cay dua)) ban thanh hoi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty nang ((dau hoi) OR (dan hoi)). hieu ve ((cam dua) OR (cay dua)) ban thanh hoi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty nang ((dau hoi) OR (dan hoi)). hieu ve ((cam dua) or (cay dua)) ban thanh hoi cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang ((dau hoi) OR (dan hoi)). hieu ve ((cam dua) or (cay dua)) ban thanh hoi cua tre*.