Perhaps you should try some spelling variations:
doanh van » doan van, doanh va, doanh ban
danh vai » danh sai, danh va, dang van
cua tre » cua te, cuu tre, cua triet
dang xa » dang xay, lang xa, dang va
hieu ve » hieu va, hieu van
dang ha » dong ha, dung ha, lang ha
cac tu » cac thu, cach tu, cac du
ve cac » va cac, vien cac

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu cac ky ((dang xa) OR (dang ha)) hoi. hieu ve cac tu va ((danh vai) or (doanh van)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu cac ky ((dang xa) OR (dang ha)) hoi. hieu ve cac tu va ((danh vai) OR (doanh van)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu cac ky ((dang xa) OR (dang ha)) hoi. hieu ve cac tu va ((danh vai) or (doanh van)) cua tre".
• Adding a wildcard symbol may retrieve word variants: tu cac ky ((dang xa) OR (dang ha)) hoi. hieu ve cac tu va ((danh vai) or (doanh van)) cua tre*.