Perhaps you should try some spelling variations:
doi chieu » doi chi, ho chieu, mot chieu
tranh cai » tranh cac, trinh cai, tranh chap
cai hoang » mai hoang, cam hoang, cap hoang
vuong dan » huong dan, xuong dan, vuong dao
tuong dan » huong dan, tung dan, xuong dan
doc hieu » toc thieu, hoc thieu, hoc hien
than tap » toan tap, han tap, phan tap

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 cai hoang ((vuong dan) OR (tuong dan)) than tap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((doi chieu) OR (doc hieu)) sach - canh tranh cai hoang ((vuong dan) OR (tuong dan)) than tap.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((doi chieu) or (doc hieu)) sach - canh tranh cai hoang ((vuong dan) OR (tuong dan)) than tap".
• Adding a wildcard symbol may retrieve word variants: ((doi chieu) or (doc hieu)) sach - canh tranh cai hoang ((vuong dan) OR (tuong dan)) than tap*.