Perhaps you should try some spelling variations:
danh doi » danh di, thanh doi, dung doi
tu sach » thu sach, su sach, te sach
doi cua » dai cua, hoi cua
xa danh » va danh, dia danh, nam danh
cac tac » cac toc, cac bac, cac dac
cac tuc » cac toc, cac tu, cac nuoc
sach ky » sac ky, sach y, sach ty
cua tre » cua te, cuu tre, cua triet
hieu ve » hieu va, hieu van
nang ma » tang ma, nang cao, mang may
sang ma » tang ma, sang tao, mang may

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 ((sang ma) or (nang ma)) hoi. hieu ve ((cac tuc) OR (cac tac)) xa danh doi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((sang ma) OR (nang ma)) hoi. hieu ve ((cac tuc) OR (cac tac)) xa danh doi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky ((sang ma) or (nang ma)) hoi. hieu ve ((cac tuc) OR (cac tac)) xa danh doi cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ky ((sang ma) or (nang ma)) hoi. hieu ve ((cac tuc) OR (cac tac)) xa danh doi cua tre*.