Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
than soc » than doc, than hoc, than so
qua than » qua thanh, qua phan, qua tan
thanh vi » hanh vi, thanh va, thanh ve
trung ha » trung hoc, trung tam, trung cap
cua tre » cua te, cua triet, dua tren
soc ban » hoc ban, coc ban, so ban
cuu tre » cau tren, cau treo
tang ha » lang ha, tang ma, tang van
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: ve cac ky ((tang ha) OR (trung ha)) hoi. hieu qua than soc ban thanh vi ((cua tre) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ve cac ky ((tang ha) OR (trung ha)) hoi. hieu qua than soc ban thanh vi ((cua tre) OR (cuu tre))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "ve cac ky ((tang ha) OR (trung ha)) hoi. hieu qua than soc ban thanh vi ((cua tre) or (cuu tre))*".