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