Perhaps you should try some spelling variations:
hanh tai » thanh tai, hang tai, han tai
thu sach » tu sach, thuat sach, thuoc sach
ban hanh » ban hang
tu cach » tu cac
tuc ban » thuc ban, truc ban, tu ban
cac tuc » cac toc, cac tu, cac tac
hieu ve » hieu va, hieu van
mai hoi » mai khoi, dai hoi, lai hoi
ky sang » ky nang, ky dang, ky tang
cuc tre » duc tre, cua tre, cuu tre
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: ((tu cach) or (thu sach)) ky sang ((xa hoi) or (mai hoi)). hieu ve cac tuc ban hanh tai cuc tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu cach) OR (thu sach)) ky sang ((xa hoi) OR (mai hoi)). hieu ve cac tuc ban hanh tai cuc tre.
• Adding a wildcard symbol may retrieve word variants: ((tu cach) or (thu sach)) ky sang ((xa hoi) or (mai hoi)). hieu ve cac tuc ban hanh tai cuc tre*.