Perhaps you should try some spelling variations:
doi chieu » doi chi, ho chieu, mot chieu
cua nhung » va nhung
dung doan » dung doanh, dung dan, dung toan
doan phan » doanh phan, toan phan, dan phan
doc hieu » toc thieu, hoc thieu, hoc hien
cua rung » cua trung, cua rang, cua truong
phan dau » phan tu, hang dau

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 - canh tranh ((cua rung) or (cua nhung)) dung doan phan dau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((doi chieu) OR (doc hieu)) sach - canh tranh ((cua rung) OR (cua nhung)) dung doan phan dau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((doi chieu) OR (doc hieu)) sach - canh tranh ((cua rung) or (cua nhung)) dung doan phan dau".
• Adding a wildcard symbol may retrieve word variants: ((doi chieu) OR (doc hieu)) sach - canh tranh ((cua rung) or (cua nhung)) dung doan phan dau*.