Perhaps you should try some spelling variations:
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
xuc van » duc van, luc van, vuc van
sach vu » sach va, sach tu, sach uu
hieu va » lieu va, hieu qua
nang ma » sang ma, nang cao, mang may
tang ma » mang may, tang van
su viet » so viet
va cam » va cham, va cac, va cao

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) or (tang ma)) hoi. hieu va cam xuc 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 ma) OR (tang ma)) hoi. hieu va cam xuc 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 ma) or (tang ma)) hoi. hieu va cam xuc van hanh ki ((su triet) OR (su viet))".
• Adding a wildcard symbol may retrieve word variants: tu sach vu ((nang ma) or (tang ma)) hoi. hieu va cam xuc van hanh ki ((su triet) OR (su viet))*.