Perhaps you should try some spelling variations:
ban thanh » ban hang
hieu van » hieu va, thien van, lieu va
ban hanh » ban hang
thu sac » thu sach, thu san, thu xac
van chu » van chi, van phu, van cau
chu tre » cho tre, chu tri, cuu tre
sac ky » cac ky, sai ky
ma hoi » mai hoi, xa hoi, me hoi
nam di » nam doi, nam da, nam do

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sac ky nang ((ma hoi) or (ma hoa)). hieu van nam di ((ban thanh) or (ban hanh)) van chu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sac ky nang ((ma hoi) OR (ma hoa)). hieu van nam di ((ban thanh) OR (ban hanh)) van chu tre.
• Adding a wildcard symbol may retrieve word variants: thu sac ky nang ((ma hoi) or (ma hoa)). hieu van nam di ((ban thanh) or (ban hanh)) van chu tre*.