Perhaps you should try some spelling variations:
quang quan » quang tuan, quan quan, quang xuan
tinh thong » tinh thuong, trinh thong, tinh khong
quang uan » quang tuan, quang ban, quang tran
hieu soat » hieu suat, hieu hoat, hieu luat
tien soat » trien hoat, thien hoat, kiem soat
van hieu » cao hieu
quan van » luan van, quan va, quan luan
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: (( tinh ((quang quan) or (quang uan)) van hieu soat ) or ( tinh thong quan van tien soat ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tinh ((quang quan) OR (quang uan)) van hieu soat ) OR ( tinh thong quan van tien soat )).
• Adding a wildcard symbol may retrieve word variants: (( tinh ((quang quan) or (quang uan)) van hieu soat ) or ( tinh thong quan van tien soat ))*.