Perhaps you should try some spelling variations:
ban thanh » ban hanh
ban hang » ngan hang
hieu van » hieu va, thien van, lieu va
cua tre » cua te, cuu tre, cua triet
hai cua » thai cua, dai cua, hoi cua
van cam » van nam, van lam, van cau
cam duc » cam xuc, cao duc, pham duc
nang xa » nang x, lang xa, nang ma
sac ky » cac ky

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

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