Perhaps you should try some spelling variations:
"so sach tran cong khi đong luc" » "so sach tran hong khi đong luc", "so sach trien cong khi đong luc", "so sach tran hoang khi đong luc", "so sach tranh cong khi đong luc", "so sach tren cong khi đong luc", "so vach tran cong khi đong luc", "so sach tran cong thai đong luc", "so sach tran khong khi đong luc", "so sach tran cong ha đong luc", "so sanh tran cong khi đong luc", "bo sach tran cong khi đong luc", "co sach tran cong khi đong luc"
"su canh tranh co khi đong luc" » "su canh trinh co khi đong luc", "su canh tranh o khi đong luc", "su canh tranh cuoc khi đong luc", "suc canh tranh co khi đong luc", "su can tranh co khi đong luc", "su anh tranh co khi đong luc"

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

• If you are trying to use Boolean operators, they must be ALL CAPS: (("su canh tranh co khi đong luc") OR ("so sach tran cong khi đong luc"))~.
• Removing quotes may allow a broader search: (( su canh tranh co khi đong luc ) or ( so sach tran cong khi đong luc ))~.
• Adding a wildcard symbol may retrieve word variants: (("su canh tranh co khi đong luc") or ("so sach tran cong khi đong luc"))*.