Perhaps you should try some spelling variations:
"so sach trinh co khi đong luc" » "so sach tranh co khi đong luc", "so hanh trinh co khi đong luc", "so sach kinh co khi đong luc", "so sach trinh do khi đong luc", "so sach trinh cong khi đong luc", "so sach trinh hoa khi đong luc", "so sanh trinh co khi đong luc", "bo sach trinh co khi đong luc", "co sach trinh co khi đong luc"
"co canh tranh buoc khoi đong luc" » "co canh tranh cuoc khoi đong luc", "co canh tranh duoc khoi đong luc", "co canh tran quoc khoi đong luc", "co canh tranh quoc hoi đong luc", "co canh tranh hoc khoi đong luc", "co canh tranh duoc hoi đong luc", "bo canh tranh buoc khoi đong luc", "co anh tranh buoc khoi đong luc", "co cach tranh buoc khoi đong luc"

Try widening your search to All Fields.

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("so sach trinh co khi đong luc") or ("co canh tranh buoc khoi đong luc"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("so sach trinh co khi đong luc") OR ("co canh tranh buoc khoi đong luc")).
• Removing quotes may allow a broader search: (( so sach trinh co khi đong luc ) or ( co canh tranh buoc khoi đong luc )).
• Adding a wildcard symbol may retrieve word variants: (("so sach trinh co khi đong luc") or ("co canh tranh buoc khoi đong luc"))*.