Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
van tham » van thanh, van tuan, van chat
tu sach » thu sach, su sach, te sach
sach vu » sach va, sach tu, sach uu
hanh ki » hanh vi, hanh ky, hanh kien
xuc van » duc van, luc van, vuc van
va tham » va cham, va thanh, va thuat
vu nang » vuc nang, va nang, vu dang
su viet » so viet
ma hoi » mai hoi, ma hoa, me hoi
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: tu sach vu nang ((ma hoi) or (xa hoi)). hieu ((va tham) OR (van tham)) xuc van hanh ki su viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach vu nang ((ma hoi) OR (xa hoi)). hieu ((va tham) OR (van tham)) xuc van hanh ki su viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach vu nang ((ma hoi) or (xa hoi)). hieu ((va tham) OR (van tham)) xuc van hanh ki su viet".
• Adding a wildcard symbol may retrieve word variants: tu sach vu nang ((ma hoi) or (xa hoi)). hieu ((va tham) OR (van tham)) xuc van hanh ki su viet*.