Perhaps you should try some spelling variations:
"su sach trinh dung chi đong luc" » "su sach tranh dung chi đong luc", "su hanh trinh dung chi đong luc", "su sach kinh dung chi đong luc", "su sach trinh dung cho đong luc", "su sach trinh dung thi đong luc", "su sach trinh dung chien đong luc", "so sach trinh dung chi đong luc", "vu sach trinh dung chi đong luc"
"su dan trinh co khi đong luc" » "su dan tinh co khi đong luc", "su van trinh co khi đong luc", "su hanh trinh co khi đong luc", "su dan trinh do khi đong luc", "su dan trinh cong khi đong luc", "su dan trinh hoa khi đong luc", "su dang trinh co khi đong luc", "cu dan trinh co khi đong luc", "so dan trinh co khi 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: (("su dan trinh co khi đong luc") or ("su sach trinh dung chi đong luc"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("su dan trinh co khi đong luc") OR ("su sach trinh dung chi đong luc")).
• Removing quotes may allow a broader search: (( su dan trinh co khi đong luc ) or ( su sach trinh dung chi đong luc )).
• Adding a wildcard symbol may retrieve word variants: (("su dan trinh co khi đong luc") or ("su sach trinh dung chi đong luc"))*.