Perhaps you should try some spelling variations:
ban hang » ngan hang
tien cua » trien cua, tiep cua, dien cua
sanh ky » sang ky, nganh ky, thanh ky
hanh ky » hanh kem
qua cac » cua cac
cac tac » cac toc, cac bac, cac dac
cua tre » cua te, cuu tre, cua triet
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: so ((sanh ky) OR (hanh ky)) nang x hoi. hieu qua cac tac ((ban hanh) or (ban hang)) tien cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so ((sanh ky) OR (hanh ky)) nang x hoi. hieu qua cac tac ((ban hanh) OR (ban hang)) tien cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so ((sanh ky) OR (hanh ky)) nang x hoi. hieu qua cac tac ((ban hanh) or (ban hang)) tien cua tre".
• Adding a wildcard symbol may retrieve word variants: so ((sanh ky) OR (hanh ky)) nang x hoi. hieu qua cac tac ((ban hanh) or (ban hang)) tien cua tre*.