Perhaps you should try some spelling variations:
doanh van » doan van, doanh va, doanh ban
hieu van » thien van, lieu va, hieu ve
sach dao » lanh dao
va doanh » van doanh, vay doanh, va danh
van cua » vang cua, ban cua, dan cua
cau duc » cao duc, cau luc, chu duc
hieu va » lieu va, hieu qua
tu sach » thu sach, su sach, te sach
lang xa » dang xay, lang van
lang ha » long ha
cua tre » cua te, cuu tre, cua triet

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach dao ((lang xa) or (lang ha)) hoi. ((hieu van) or (hieu va)) cau duc va doanh van cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach dao ((lang xa) OR (lang ha)) hoi. ((hieu van) OR (hieu va)) cau duc va doanh van cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sach dao ((lang xa) or (lang ha)) hoi. ((hieu van) or (hieu va)) cau duc va doanh van cua tre*.