Perhaps you should try some spelling variations:
trinh quan » tinh quang, trinh luat, trinh han
quan quang » qua quang, quan quan, quat quang
tinh khung » trinh khung, tinh hung, tinh khang
khung luan » chung luan, dung luan, hang luan
quang van » quang ban, quan van, quang uan
hieu soat » hieu suat, hieu hoat, hieu luat
tien soat » trien hoat, thien hoat, kiem soat
van hieu » cao hieu
van tien » toan tien, van tuan

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 quang van hieu soat ) or ( tinh khung luan van tien soat ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( trinh quan quang van hieu soat ) OR ( tinh khung luan van tien soat )).
• Adding a wildcard symbol may retrieve word variants: (( trinh quan quang van hieu soat ) or ( tinh khung luan van tien soat ))*.