Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
nang tai » hang tai, tang tai, sang tai
van hanh » van thanh, ban hanh, van anh
sach vu » sach va, sach tu, sach uu
hanh ki » hanh vi, hanh ky, hanh kien
vuc van » duc van, luc van, thuc van
tu sach » thu sach, su sach, te sach
tai hoi » tai khoi, dai hoi, tai hai
vu nang » vuc nang, va nang, vu dang
va dai » va dao, vi dai, va dau
va cao » va cac, va co, va dao
va cai » va cac, va bai
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 tai hoi. hieu ((((va cai) OR (va dai))) or (va cao)) vuc van hanh ki su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach vu nang tai hoi. hieu ((((va cai) OR (va dai))) OR (va cao)) vuc van hanh ki su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach vu nang tai hoi. hieu ((((va cai) OR (va dai))) or (va cao)) vuc van hanh ki su triet".
• Adding a wildcard symbol may retrieve word variants: tu sach vu nang tai hoi. hieu ((((va cai) OR (va dai))) or (va cao)) vuc van hanh ki su triet*.