Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
ban hanh » ban hang
hanh vai » hanh vi, hanh va, hanh tai
vien cac » vien bach, vien dai, vien da
sach ky » sac ky, sach y, sach ty
lang xa » lang ha, dang xay, lang van
ky lang » ky nang, ky dang, ky tang
cua tre » cua te, cuu tre, cua triet
tu sach » thu sach, su sach, te sach
ve cac » va cac

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 ky lang xa hoi. hieu ((ve cac) OR (vien cac)) cua ban hanh vai ((cua tre) or (su triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky lang xa hoi. hieu ((ve cac) OR (vien cac)) cua ban hanh vai ((cua tre) OR (su triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky lang xa hoi. hieu ((ve cac) OR (vien cac)) cua ban hanh vai ((cua tre) or (su triet))".
• Adding a wildcard symbol may retrieve word variants: tu sach ky lang xa hoi. hieu ((ve cac) OR (vien cac)) cua ban hanh vai ((cua tre) or (su triet))*.