Perhaps you should try some spelling variations:
nang tai » hang tai, tang tai, sang tai
su triet » su tien, ve triet
van hanh » van thanh, ban hanh, van anh
tu sach » thu sach, su sach, te sach
hanh ki » hanh vi, hanh ky, hanh kien
vuc van » duc van, luc van, thuc van
su viet » so viet
sach vu » sach va, sach tu, sach uu
tai hoi » tai khoi, dai hoi, tai hai
vu nang » vuc nang, va nang, vu dang
va cai » va cac, va bai, va dai
va cao » va cac, va co, va dao

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 tai hoi. hieu ((va cai) or (va cao)) vuc van hanh ki ((su triet) OR (su viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach vu nang tai hoi. hieu ((va cai) OR (va cao)) vuc van hanh ki ((su triet) OR (su viet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach vu nang tai hoi. hieu ((va cai) or (va cao)) vuc van hanh ki ((su triet) OR (su viet))".
• Adding a wildcard symbol may retrieve word variants: tu sach vu nang tai hoi. hieu ((va cai) or (va cao)) vuc van hanh ki ((su triet) OR (su viet))*.