Perhaps you should try some spelling variations:
tan thanh » tran thanh, tang thanh, toan thanh
thanh de » hanh de, thanh ve, thanh do
ky tang » ky nang, ky dang, kho tang
van hoi » van hoa, van hoe, van loi
van hoc » van hoa
cua tre » cua te, cuu tre, cua triet
va cam » va cham, va cao, va cai
de cua » le cua, te cua, dieu cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu cac ky tang ((van hoi) or (van hoc)). hieu ((va cam) OR (va cac)) duc tan thanh de cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu cac ky tang ((van hoi) OR (van hoc)). hieu ((va cam) OR (va cac)) duc tan thanh de cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu cac ky tang ((van hoi) or (van hoc)). hieu ((va cam) OR (va cac)) duc tan thanh de cua tre".
• Adding a wildcard symbol may retrieve word variants: tu cac ky tang ((van hoi) or (van hoc)). hieu ((va cam) OR (va cac)) duc tan thanh de cua tre*.