Perhaps you should try some spelling variations:
ban thanh » ban hang
thu sach » thuat sach, thuoc sach, thu hoach
ban hanh » ban hang
tu sach » su sach, te sach, tu cach
tai cua » thai cua, tai cuc, tri cua
cua tre » cua te, cuu tre, cua triet
cam cuc » cam xuc, cham cuu, pham cuc
hieu ve » hieu va, hieu van
cao hoc » co hoc, cho hoc, chat hoc
ve cam » ve cham, ve cac, va cam

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) or (thu sach)) ky nang cao hoc. hieu ve cam cuc ((ban thanh) OR (ban hanh)) tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) ky nang cao hoc. hieu ve cam cuc ((ban thanh) OR (ban hanh)) tai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (thu sach)) ky nang cao hoc. hieu ve cam cuc ((ban thanh) OR (ban hanh)) tai cua tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thu sach)) ky nang cao hoc. hieu ve cam cuc ((ban thanh) OR (ban hanh)) tai cua tre*.