Perhaps you should try some spelling variations:
thieu sach » chieu sach, thien hach, theo sach
hieu cach » hieu cac, chieu sach, hieu ca
luong nin » luong ninh, luong tin, luong nan
van hung » van dung, manh hung, van duong
nin toan » tinh toan
toan tap » toan ban
va hung » va nhung, va huong, va ung

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((thieu sach) or (hieu cach)) - canh tranh ((va hung) OR (van hung)) luong nin toan tap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((thieu sach) OR (hieu cach)) - canh tranh ((va hung) OR (van hung)) luong nin toan tap*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((thieu sach) or (hieu cach)) - canh tranh ((va hung) OR (van hung)) luong nin toan tap*".