Perhaps you should try some spelling variations:
va trien » va truyen, va thiet, va tuyen
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
te sach » toc sach
ma hoi » mai hoi, xa hoi, ma hoa
ve cac » va cac, vien cac
te sac » te cac, te san
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) OR (te sach)) ky nang ma hoi. hieu ve cac ((duc van) or (hoc can)) hanh vi va trien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sac) OR (te sach)) ky nang ma hoi. hieu ve cac ((duc van) OR (hoc can)) hanh vi va trien.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sac) OR (te sach)) ky nang ma hoi. hieu ve cac ((duc van) or (hoc can)) hanh vi va trien".
• Adding a wildcard symbol may retrieve word variants: ((te sac) OR (te sach)) ky nang ma hoi. hieu ve cac ((duc van) or (hoc can)) hanh vi va trien*.