Perhaps you should try some spelling variations:
qua thai » qua hai, qua khai, qua tai
cau tren » cu tren, dau tren, ca tren
ky lang » ky nang, ky dang, ky tang
van hoi » van hoa, van hoe, van loi
van hoc » van hoa
thai do » thay doi, thai den
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, cua triet
te san » te ban, ke san, tu san
san ky » sang ky, van ky, dan ky
do va » do van, so va

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

• Performing a fuzzy search may retrieve terms with similar spellings: te san ky lang ((van hoi) OR (van hoc)). hieu qua thai do va hanh vi ((cau tren) or (cua tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te san ky lang ((van hoi) OR (van hoc)). hieu qua thai do va hanh vi ((cau tren) OR (cua tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "te san ky lang ((van hoi) OR (van hoc)). hieu qua thai do va hanh vi ((cau tren) or (cua tre))".
• Adding a wildcard symbol may retrieve word variants: te san ky lang ((van hoi) OR (van hoc)). hieu qua thai do va hanh vi ((cau tren) or (cua tre))*.