Perhaps you should try some spelling variations:
doanh vang » doanh van, doanh sang, doanh quang
vang cua » mang cua, hang cua, tang cua
lang van » dang van, tang van, hoang van
toc sac » toc sach, toc san, hoc sach
hieu ve » hieu va, hieu van
lang xa » lang ha, dang xay
cua tre » cua te, cuu tre, cua triet
sac ky » cac ky, sai ky
ve cac » va cac, vien cac
tuc va » thuc va, truc va, duc va

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sac ky ((lang xa) or (lang van)) hoi. hieu ve cac ((tuc va) OR (tuc xa)) doanh vang cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sac ky ((lang xa) OR (lang van)) hoi. hieu ve cac ((tuc va) OR (tuc xa)) doanh vang cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sac ky ((lang xa) or (lang van)) hoi. hieu ve cac ((tuc va) OR (tuc xa)) doanh vang cua tre*".