Perhaps you should try some spelling variations:
doi chieu » doi chi, ho chieu, mot chieu
tuan hang » tuan hoang, tuan bang, tuan dang
hang cong » dang cong, hang nong, bang cong
doc hieu » toc thieu, hoc thieu, hoc hien
san tuan » van tuan, san luan, san quan
tac toan » tam toan, hach toan, tich toan
tap toan » tap doan, tap quan, bai toan

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((doi chieu) or (doc hieu)) sach - thanh san tuan hang cong ((tac toan) OR (tap toan)) ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((doi chieu) OR (doc hieu)) sach - thanh san tuan hang cong ((tac toan) OR (tap toan)) ban.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((doi chieu) or (doc hieu)) sach - thanh san tuan hang cong ((tac toan) OR (tap toan)) ban".
• Adding a wildcard symbol may retrieve word variants: ((doi chieu) or (doc hieu)) sach - thanh san tuan hang cong ((tac toan) OR (tap toan)) ban*.