Perhaps you should try some spelling variations:
sach tranh » canh tranh
tranh cong » thanh cong, trinh cong, tran cong
sanh ngon » danh ngon, canh ngon, sach ngon
cong khi » cong thai, khong khi, co khi
doc khi » doi khi, hoc khoi, dong khi
hoc khi » hoc khoi, hoc khia, hoc ki
co sach » bo sach, cuon sach, hoc sach

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( do sanh ngon ((doc khi) OR (hoc khi)) đong luc ) or ( co sach tranh cong khi đong luc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( do sanh ngon ((doc khi) OR (hoc khi)) đong luc ) OR ( co sach tranh cong khi đong luc )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( do sanh ngon ((doc khi) OR (hoc khi)) đong luc ) or ( co sach tranh cong khi đong luc ))".
• Adding a wildcard symbol may retrieve word variants: (( do sanh ngon ((doc khi) OR (hoc khi)) đong luc ) or ( co sach tranh cong khi đong luc ))*.