Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
thanh vi » hanh vi, thanh va, thanh ve
cua tre » cua te, cuu tre, cua triet
cac tac » cac toc, cac bac, cac dac
cac tuc » cac toc, cac tu, cac nuoc
hieu va » lieu va, hieu qua
tang ma » mang may, tang van
ma hoi » mai hoi, xa hoi, ma hoa
cai ky » cao ky, cac ky, sai ky
cam ky » cao ky, cac ky
vi cua » vai cua, di cua

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

• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((cai ky) OR (cam ky)) tang ma hoi. hieu va ((cac tuc) OR (cac tac)) ban thanh vi cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((cai ky) or (cam ky)) tang ma hoi. hieu va ((cac tuc) OR (cac tac)) ban thanh vi cua tre~".
• Adding a wildcard symbol may retrieve word variants: tu ((cai ky) or (cam ky)) tang ma hoi. hieu va ((cac tuc) OR (cac tac)) ban thanh vi cua tre*.