Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
ban hanh » ban hang
dua tren » dung tren
nam xua » nam cua, nam mua, nam qua
ban anh » ban banh, ban danh, bang anh
cua tre » cua te, cuu tre, cua triet
tu sac » tu sach, tu cac, tu san
sac ky » cac ky, sai ky
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sac ky nang x hoi. hieu van nam xua ((ban anh) OR (ban hanh)) ve ((dua tren) or (cua tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sac ky nang x hoi. hieu van nam xua ((ban anh) OR (ban hanh)) ve ((dua tren) OR (cua tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sac ky nang x hoi. hieu van nam xua ((ban anh) OR (ban hanh)) ve ((dua tren) or (cua tre))".
• Adding a wildcard symbol may retrieve word variants: tu sac ky nang x hoi. hieu van nam xua ((ban anh) OR (ban hanh)) ve ((dua tren) or (cua tre))*.