Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
hanh via » hanh vi, hanh va, anh va
sach ky » sac ky, sach y, sach ty
cua tre » cua te, cuu tre, dua tren
va hanh » van hanh, va thanh, va danh
su sach » so sach, vu sach
nang ma » tang ma, sang ma, nang cao
hieu va » lieu va
bao do » ban do, dao do, cao do
ma hoi » mai hoi, xa hoi, ma hoa
do va » do van, so va

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ky nang ma hoi. ((hieu va) OR (hieu qua)) bao do va hanh via ((cua tre) or (cua triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang ma hoi. ((hieu va) OR (hieu qua)) bao do va hanh via ((cua tre) OR (cua triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky nang ma hoi. ((hieu va) OR (hieu qua)) bao do va hanh via ((cua tre) or (cua triet))".
• Adding a wildcard symbol may retrieve word variants: su sach ky nang ma hoi. ((hieu va) OR (hieu qua)) bao do va hanh via ((cua tre) or (cua triet))*.