Perhaps you should try some spelling variations:
"vu tich nguoi cong khi đong luc" » "vu toc nguoi cong khi đong luc", "vu tich nguoi muong khi đong luc", "vu tich nguoi thong khi đong luc", "vu tich nguoi nung khi đong luc", "vu tich nguoi cong thai đong luc", "vu tich nguoi khong khi đong luc", "vu tich nguoi cong ha đong luc", "su tich nguoi cong khi đong luc", "va tich nguoi cong khi đong luc", "suc tich nguoi cong khi đong luc"
"su sach ngonh co khi đong luc" » "su sach ngon co khi đong luc", "su sach ngan co khi đong luc", "su sach nganh co khi đong luc", "su sach ninh co khi đong luc", "so sach ngonh co khi đong luc", "vu sach ngonh 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 sach ngonh co khi đong luc") or ("vu tich nguoi cong khi đong luc"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("su sach ngonh co khi đong luc") OR ("vu tich nguoi cong khi đong luc")).
• Removing quotes may allow a broader search: (( su sach ngonh co khi đong luc ) or ( vu tich nguoi cong khi đong luc )).
• Adding a wildcard symbol may retrieve word variants: (("su sach ngonh co khi đong luc") or ("vu tich nguoi cong khi đong luc"))*.