Perhaps you should try some spelling variations:
trinh quan » tinh quang, trinh luat, trinh han
thien hoat » trien hoat, thien thuat, tien hoa
quan hang » quan hoang, quan lang, quan hanh
hieu suat » hieu luat, hieu qua
dung pham » dung phan, hung pham, tung pham
tien soat » trien hoat, kiem soat, tien hoa
va hieu » van hieu, va dieu, va hien

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( trinh quan hang va hieu suat ) or ( tin dung pham van ((tien soat) OR (thien hoat)) ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( trinh quan hang va hieu suat ) OR ( tin dung pham van ((tien soat) OR (thien hoat)) )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( trinh quan hang va hieu suat ) or ( tin dung pham van ((tien soat) OR (thien hoat)) ))".
• Adding a wildcard symbol may retrieve word variants: (( trinh quan hang va hieu suat ) or ( tin dung pham van ((tien soat) OR (thien hoat)) ))*.