Perhaps you should try some spelling variations:
ban thanh » ban hang
trung ha » trung hoc, trung cap
qua thai » qua hai, qua khai, qua tai
ban hanh » ban hang
thai do » thay doi, thai den
cua tre » cua te, cuu tre, cua triet
te cac » tu cac, ve cac, te cao
vi cua » vai cua, di cua

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

• If you are trying to use Boolean operators, they must be ALL CAPS: te cac ky ((trung ha) OR (trung tam)) hoi. hieu qua thai do ((ban thanh) OR (ban hanh)) vi cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te cac ky ((trung ha) OR (trung tam)) hoi. hieu qua thai do ((ban thanh) or (ban hanh)) vi cua tre~".
• Adding a wildcard symbol may retrieve word variants: te cac ky ((trung ha) OR (trung tam)) hoi. hieu qua thai do ((ban thanh) or (ban hanh)) vi cua tre*.