Perhaps you should try some spelling variations:
duoc cach » cuoc cach, duoc cac, truoc cach
cach ky » cac ky
hieu ve » hieu va, hieu van
ve pham » vi pham, v pham, ve phan
va hanh » van hanh, va thanh, va danh
cu tren » tu tren, dua tren
cua te » cua tu
o hoi » co hoi, o hai, o hoa
o hoc » co hoc, mo hoc, so hoc

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

• Performing a fuzzy search may retrieve terms with similar spellings: duoc cach ky nang ((o hoi) OR (o hoc)). hieu ve pham duc va hanh vi ((cua te) or (cu tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: duoc cach ky nang ((o hoi) OR (o hoc)). hieu ve pham duc va hanh vi ((cua te) OR (cu tren))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "duoc cach ky nang ((o hoi) OR (o hoc)). hieu ve pham duc va hanh vi ((cua te) or (cu tren))*".