Perhaps you should try some spelling variations:
hieu cua » hieu qua, dieu cua, bieu cua
va hanh » van hanh, va thanh, ban hanh
va danh » va dinh, va dan, dia danh
cac xuc » cam xuc, cac nuoc, chat xuc
cua tre » cua te, cuu tre, cua triet
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
ca cua » co cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu ((cai ky) OR (cam ky)) tang ma hoi. hieu cua cac xuc ((va danh) or (va hanh)) ca cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((cai ky) OR (cam ky)) tang ma hoi. hieu cua cac xuc ((va danh) OR (va hanh)) ca 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 cua cac xuc ((va danh) or (va hanh)) ca cua tre".
• Adding a wildcard symbol may retrieve word variants: tu ((cai ky) OR (cam ky)) tang ma hoi. hieu cua cac xuc ((va danh) or (va hanh)) ca cua tre*.