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

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