Perhaps you should try some spelling variations:
luoc dai » cuoc doi, hoc dai, duc dai
va trien » va truyen, va thiet, va tuyen
hieu va » lieu va, hieu qua
duc van » duc va, duc tan, duc manh
te sac » te sach, te cac, te san
sac ky » cac ky, sai ky
ma hoi » mai hoi, ma hoa, me hoi
vi va » vi van, vai va, vu 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 sac ky nang ((ma hoi) or (xa hoi)). hieu va cac ((duc van) or (luoc dai)) hanh vi va trien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sac ky nang ((ma hoi) OR (xa hoi)). hieu va cac ((duc van) OR (luoc dai)) hanh vi va trien.
• Adding a wildcard symbol may retrieve word variants: te sac ky nang ((ma hoi) or (xa hoi)). hieu va cac ((duc van) or (luoc dai)) hanh vi va trien*.