Perhaps you should try some spelling variations:
doanh van » doan van, doanh va, doanh ban
danh vai » danh sai, danh va, dang van
cuu tre » cua tre, cau tren, cau treo
lang xa » lang ha, dang xay, lang van
hieu ve » hieu va, hieu van
cac tu » cac thu, cach tu, cac du
sac ky » sai ky
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 ((sac ky) OR (cac ky)) lang xa hoi. hieu ve cac tu va ((danh vai) or (doanh van)) cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sac ky) OR (cac ky)) lang xa hoi. hieu ve cac tu va ((danh vai) OR (doanh van)) cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sac ky) OR (cac ky)) lang xa hoi. hieu ve cac tu va ((danh vai) or (doanh van)) cuu tre".
• Adding a wildcard symbol may retrieve word variants: tu ((sac ky) OR (cac ky)) lang xa hoi. hieu ve cac tu va ((danh vai) or (doanh van)) cuu tre*.