Perhaps you should try some spelling variations:
"su sach trinh my khi đong luc" » "su sach tranh my khi đong luc", "su hanh trinh my khi đong luc", "su sach kinh my khi đong luc", "su sach trinh may khi đong luc", "su sach trinh ky khi đong luc", "su sach trinh ly khi đong luc", "so sach trinh my khi đong luc", "vu sach trinh my khi đong luc", "su sach trinh my chi đong luc"
"su canh tranh my khi đong luc" » "su canh tran sy khi đong luc", "su canh anh my khi đong luc", "su canh tran mi khi đong luc", "suc canh tranh my khi đong luc", "su can tranh my khi đong luc", "su anh tranh my khi đong luc", "su canh tranh ly khi đong luc", "su canh tranh ky khi đong luc", "su canh tranh my chi đong luc"

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

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