Perhaps you should try some spelling variations:
dung tuong » dung thuong, dung truong, dung trong
hieu cach » hieu cac, chieu sach, hieu ca
van thanh » ban thanh, van tuan
tran xuan » tran quang, tran van
hoc hieu » hoc thieu, hoc hien, doc hieu
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: hoc hieu cach - thanh ((van thanh) or (tran xuan)) dung tuong ((tac toan) OR (tap toan)) ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hieu cach - thanh ((van thanh) OR (tran xuan)) dung tuong ((tac toan) OR (tap toan)) ban.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc hieu cach - thanh ((van thanh) or (tran xuan)) dung tuong ((tac toan) OR (tap toan)) ban".
• Adding a wildcard symbol may retrieve word variants: hoc hieu cach - thanh ((van thanh) or (tran xuan)) dung tuong ((tac toan) OR (tap toan)) ban*.