Perhaps you should try some spelling variations:
phan thanh » pham thanh, ban thanh, van thanh
hieu soat » hieu suat, hieu hoat, hieu luat
van viet » san viet, gian viet, tran viet
viet dat » viec dat, viet da, viet dao
van hieu » cao hieu
pho van » ho van, phi van, tho van
tin » tinh
luan » quan, lan

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( tin dung luan van viet dat ) or ( phan thanh pho van hieu soat ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tin dung luan van viet dat ) OR ( phan thanh pho van hieu soat ))*.