Perhaps you should try some spelling variations:
va triet » va thiet, va trien, ve triet
hanh vai » hanh vi, hanh va, hanh tai
va hanh » van hanh, va thanh, va danh
sach ky » sac ky, sach y, sach ty
tu sach » thu sach, su sach, te sach
ky sang » ky nang, ky dang, ky tang
ve cac » va cac, vien cac
ma hoi » mai hoi, ma hoa, me hoi
xuc va » duc va, tuc va, luc va
vai va » mai va, dai va, hai va
ve cam » ve cham, va cam, ve cai

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 ky sang ((ma hoi) or (xa hoi)). hieu ((ve cam) OR (ve cac)) xuc va hanh vai va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky sang ((ma hoi) OR (xa hoi)). hieu ((ve cam) OR (ve cac)) xuc va hanh vai va triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky sang ((ma hoi) or (xa hoi)). hieu ((ve cam) OR (ve cac)) xuc va hanh vai va triet".
• Adding a wildcard symbol may retrieve word variants: tu sach ky sang ((ma hoi) or (xa hoi)). hieu ((ve cam) OR (ve cac)) xuc va hanh vai va triet*.