Perhaps you should try some spelling variations:
dung phuong » dung thuong, bang phuong, dung chung
phuong hang » phuong hoang, phuong bang, phuong hanh
hang quang » dang quang, hong quang, hang quan
hieu lang » chieu sang, hieu quang, nhieu tang
quang cao » nang cao, quang nam
doc hieu » toc thieu, hoc thieu, hoc hien
tranh va » tranh van, trang va, trinh va
tran van » luan van

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

• Performing a fuzzy search may retrieve terms with similar spellings: doc hieu lang - canh ((tranh va) or (tran van)) dung phuong hang quang cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu lang - canh ((tranh va) OR (tran van)) dung phuong hang quang cao.
• Adding a wildcard symbol may retrieve word variants: doc hieu lang - canh ((tranh va) or (tran van)) dung phuong hang quang cao*.