Perhaps you should try some spelling variations:
hieu ve » hieu va, hieu van
hanh ki » hanh vi, hanh ky, hanh kien
duc van » duc tan, duc manh, duc phan
su sach » so sach, vu sach
va nang » van nang, da nang, cam nang
su viet » so viet
ma hoi » mai hoi, xa hoi, ma hoa
ve cao » va cao, ve bao, ve cac
v nang » vu nang, van nang, voi nang
ki su » ky su

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ((v nang) or (va nang)) ma hoi. hieu ve cao ((duc van) OR (duc va)) hanh ki su viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((v nang) OR (va nang)) ma hoi. hieu ve cao ((duc van) OR (duc va)) hanh ki su viet*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((v nang) or (va nang)) ma hoi. hieu ve cao ((duc van) OR (duc va)) hanh ki su viet*".