Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
thanh vi » hanh vi, thanh va, thanh ve
nganh ky » nganh y, nganh xay, hanh ky
hieu van » hieu va, thien van, lieu va
sang kyo » sang ky, sang tao, dang ky
duc ban » duc tan, duc van, dua ban
cac duc » cac du, cao duc, cac dac
van cac » van hac, van cau, van bac
cua tre » cua te, cuu tre, cua triet
tang ma » mang may, tang van
tang ha » lang ha, trung ha, tang van
vi cua » vai cua, di cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: so ((sang kyo) or (nganh ky)) ((tang ha) or (tang ma)) hoi. hieu van cac duc ban thanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so ((sang kyo) OR (nganh ky)) ((tang ha) OR (tang ma)) hoi. hieu van cac duc ban thanh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: so ((sang kyo) or (nganh ky)) ((tang ha) or (tang ma)) hoi. hieu van cac duc ban thanh vi cua tre*.