Perhaps you should try some spelling variations:
doanh van » doan van, doanh va, doanh ban
thu sach » tu sach, thuat sach, thuoc sach
va doanh » van doanh, vay doanh, va danh
hieu van » thien van, lieu va, hieu ve
hoi lang » hoa lang, hoi dan
hieu va » lieu va, hieu qua
cau duc » cao duc, cau luc, chu duc
van cua » vang cua, ban cua, dan cua
cua tre » cua te, cuu tre, cua triet
o lang » hoa lang

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach ((o lang) OR (hoi lang)) xa 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: thu sach ((o lang) OR (hoi lang)) xa hoi. ((hieu van) OR (hieu va)) cau duc va doanh van cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ((o lang) OR (hoi lang)) xa hoi. ((hieu van) or (hieu va)) cau duc va doanh van cua tre*".