Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
dang xay » dang van, van xay
cua tre » cua te, cuu tre, cua triet
day cua » dai cua
va hanh » va thanh, va danh, ban hanh
cam luc » cam xuc, cau luc
hieu va » lieu va, hieu qua
lang xa » lang ha, lang van
cai ky » cao ky, cac ky, cam ky
va cam » va cham, va cac, va cao
tu cai » tu cac, tu can, tu bai

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 ((lang xa) OR (dang xay)) hoi. hieu va cam luc ((va hanh) or (van hanh)) day cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu cai ky ((lang xa) OR (dang xay)) hoi. hieu va cam luc ((va hanh) OR (van hanh)) day cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu cai ky ((lang xa) OR (dang xay)) hoi. hieu va cam luc ((va hanh) or (van hanh)) day cua tre".
• Adding a wildcard symbol may retrieve word variants: tu cai ky ((lang xa) OR (dang xay)) hoi. hieu va cam luc ((va hanh) or (van hanh)) day cua tre*.