Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
van hanh » van thanh, ban hanh, van anh
sach ty » sach y, sach tu, sach thu
va hanh » va thanh, va danh, ban hanh
tu sach » thu sach, su sach, te sach
nang ma » tang ma, sang ma, nang cao
ty nang » ky nang, ty xang, ty hang
ve cam » ve cham, va cam, ve cai
ve cac » va cac, vien cac
ma hoi » mai hoi, xa hoi, ma hoa

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