Perhaps you should try some spelling variations:
hoc can » hoc dan, hoc cao, hoc cac
duc van » duc va, duc tan, duc manh
hieu ve » hieu va, hieu van
nang ma » tang ma, sang ma, nang cao
ve cac » va cac, vien cac
sac ky » cac ky, sai ky
ma hoi » mai hoi, xa hoi, ma hoa
vai va » mai va, dai va, hai va
te sac » te sach, te cac, te san
vi va » vi van, vu va, bi 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. hieu ve cac ((duc van) or (hoc can)) hanh ((vi va) or (vai va)) trien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sac ky nang ma hoi. hieu ve cac ((duc van) OR (hoc can)) hanh ((vi va) OR (vai va)) trien.
• Adding a wildcard symbol may retrieve word variants: te sac ky nang ma hoi. hieu ve cac ((duc van) or (hoc can)) hanh ((vi va) or (vai va)) trien*.