Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
co sach » bo sach, cuon sach
cac tuc » cac toc, cac tu, cac tac
tai cua » thai cua, tai cuc, tri cua
ba dinh » va dinh, xac dinh, nam dinh
xa dinh » xac dinh, va dinh, ha dinh
cua tre » cua te, cuu tre, cua triet
hieu ve » hieu va, hieu van
hang xa » hoang xa, hang va, hang ca
ly hang » ly quang
ve cac » va cac, vien cac

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((co sach) OR (hoc sach)) ly hang xa hoi. hieu ve cac tuc ((xa dinh) or (ba dinh)) tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((co sach) OR (hoc sach)) ly hang xa hoi. hieu ve cac tuc ((xa dinh) OR (ba dinh)) tai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((co sach) OR (hoc sach)) ly hang xa hoi. hieu ve cac tuc ((xa dinh) or (ba dinh)) tai cua tre".
• Adding a wildcard symbol may retrieve word variants: ((co sach) OR (hoc sach)) ly hang xa hoi. hieu ve cac tuc ((xa dinh) or (ba dinh)) tai cua tre*.