Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
hieu van » hieu va, thien van, lieu va
van cham » van chat, van tham, va cham
cham coc » cham soc, kham cuoc, chat co
ky tang » ky nang, kho tang, ky trong
ky dang » ky nang, ky danh
coc ban » co ban, cac ban, hoc ban
hai cua » thai cua, hoi cua, lai cua
su sac » su sach, su cac, su xac

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sac ((ky tang) or (ky dang)) xa hoi. hieu van cham coc ban thanh ((hai cua) OR (dai cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sac ((ky tang) OR (ky dang)) xa hoi. hieu van cham coc ban thanh ((hai cua) OR (dai cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sac ((ky tang) or (ky dang)) xa hoi. hieu van cham coc ban thanh ((hai cua) OR (dai cua)) tre".
• Adding a wildcard symbol may retrieve word variants: su sac ((ky tang) or (ky dang)) xa hoi. hieu van cham coc ban thanh ((hai cua) OR (dai cua)) tre*.