Perhaps you should try some spelling variations:
tieu sach » chieu sach, dien sach, te sach
hang cong » hang nong, bang cong, thanh cong
dang cong » dung cong
anh tang » anh bang, anh dang, anh nang
tang cua » mang cua, hang cua, tang luan
toan cao » toan tap
toan ban » van ban

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

• Performing a fuzzy search may retrieve terms with similar spellings: theo tieu sach - anh tang cua ((hang cong) or (dang cong)) dan ((toan cao) OR (toan ban))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: theo tieu sach - anh tang cua ((hang cong) OR (dang cong)) dan ((toan cao) OR (toan ban)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "theo tieu sach - anh tang cua ((hang cong) or (dang cong)) dan ((toan cao) OR (toan ban))".
• Adding a wildcard symbol may retrieve word variants: theo tieu sach - anh tang cua ((hang cong) or (dang cong)) dan ((toan cao) OR (toan ban))*.