Perhaps you should try some spelling variations:
trinh quan » tinh quang, trinh luat, trinh han
tinh khong » tinh khang, tinh huong, benh khong
khong luan » thong luan, khong quan, khung luan
quan quan » quan quang, qua quan, quan luan
hieu soat » hieu suat, hieu hoat, hieu luat
hien soat » thien hoat, kiem soat, hien luat
bien soan » bien so
quan van » quan va, quan luan, quan doan
van hieu » cao hieu

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 quan van hieu soat ) or ( tinh khong luan van ((hien soat) OR (bien soan)) ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( trinh quan quan van hieu soat ) OR ( tinh khong luan van ((hien soat) OR (bien soan)) )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( trinh quan quan van hieu soat ) or ( tinh khong luan van ((hien soat) OR (bien soan)) ))".
• Adding a wildcard symbol may retrieve word variants: (( trinh quan quan van hieu soat ) or ( tinh khong luan van ((hien soat) OR (bien soan)) ))*.