Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
hanh vai » hanh va, hanh tai, hanh van
lang van » dang van, tang van, hoang van
van hoc » van hoa
hieu ve » hieu va, hieu van
cau cua » cau qua, ca cua, cu cua
sach ky » sac ky, sach y, sach ty
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 cau » ke cau, va cau, ve 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 van hoc. hieu ve cau cua ban ((hanh vai) OR (hanh vi)) ((cua tre) or (su triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky lang van hoc. hieu ve cau cua ban ((hanh vai) OR (hanh vi)) ((cua tre) OR (su triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky lang van hoc. hieu ve cau cua ban ((hanh vai) OR (hanh vi)) ((cua tre) or (su triet))".
• Adding a wildcard symbol may retrieve word variants: tu sach ky lang van hoc. hieu ve cau cua ban ((hanh vai) OR (hanh vi)) ((cua tre) or (su triet))*.