Perhaps you should try some spelling variations:
sach tranh » canh tranh
tranh cong » thanh cong, trinh cong, tran cong
sach ngan » sach ngon, sach nha, sach han
ngan cong » nganh cong, nganh nong, ngan hang
cong thai » cong hai, hong thai, cong thanh
cong khi » khong khi, co khi, cong ha
tu sach » thu sach, su sach, te sach

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( tu sach ngan cong thai đong luc ) or ( tu sach tranh cong khi đong luc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu sach ngan cong thai đong luc ) OR ( tu sach tranh cong khi đong luc )).
• Adding a wildcard symbol may retrieve word variants: (( tu sach ngan cong thai đong luc ) or ( tu sach tranh cong khi đong luc ))*.