Perhaps you should try some spelling variations:
thieu sach » chieu sach, thien hach, theo sach
hieu cach » hieu cac, chieu sach, hieu ca
tang luan » dung luan
hang cong » dang cong, hang nong, bang cong
tang cua » mang cua, hang cua, thong cua
cong san » cong tac
san toan » van toan, dan toan, manh toan
toan cao » toan ban, toan tap

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)) - hanh ((tang cua) or (tang luan)) hang cong san toan cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((thieu sach) OR (hieu cach)) - hanh ((tang cua) OR (tang luan)) hang cong san toan cao.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((thieu sach) OR (hieu cach)) - hanh ((tang cua) or (tang luan)) hang cong san toan cao".
• Adding a wildcard symbol may retrieve word variants: hoc ((thieu sach) OR (hieu cach)) - hanh ((tang cua) or (tang luan)) hang cong san toan cao*.