Perhaps you should try some spelling variations:
doanh van » doan van, doanh va, doanh ban
sach ky » sach y, sach ty, sach kem
van cua » vang cua, ban cua, dan cua
thuc va » thuc vat, thuc dan, thuc day
cua tre » cua te, cuu tre, cua triet
hieu ve » hieu va, hieu van
dang xa » dang xay, lang xa, dang ha
tuc va » truc va, tuc xa, duc va
sac ky » cac 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: te ((sach ky) or (sac ky)) dang xa hoi. hieu ve cac ((tuc va) OR (thuc va)) doanh van cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sach ky) OR (sac ky)) dang xa hoi. hieu ve cac ((tuc va) OR (thuc va)) doanh van cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te ((sach ky) or (sac ky)) dang xa hoi. hieu ve cac ((tuc va) OR (thuc va)) doanh van cua tre*".