Perhaps you should try some spelling variations:
luoc can » luc canh, hoc can, luoc dai
va trien » va truyen, va thiet, va tuyen
nang xa » nang x, nang ma, mang xa
lang xa » lang ha, dang xay, lang van
hieu ve » hieu va, hieu van
duc van » duc va, duc tan, duc manh
te sac » te sach, te cac, te san
sac ky » cac ky, sai ky
ve cac » va cac, vien cac
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 xa) or (lang xa)) hoi. hieu ve cac ((duc van) or (luoc can)) hanh vi va trien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sac ky ((nang xa) OR (lang xa)) hoi. hieu ve cac ((duc van) OR (luoc can)) hanh vi va trien.
• Adding a wildcard symbol may retrieve word variants: te sac ky ((nang xa) or (lang xa)) hoi. hieu ve cac ((duc van) or (luoc can)) hanh vi va trien*.