Perhaps you should try some spelling variations:
hieu quang » thieu quang, hieu quan, diep quang
tranh van » tran van, trinh van, thanh van
dang cong » dung cong
van dang » van dong, van dung, van nang
cong tac » cong ty
tac phan » tac pham, tai phan, tac phat
phan dau » phan tu, hang dau

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc ((hieu quang) OR (hieu qua)) - canh tranh van dang cong tac phan dau~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc ((hieu quang) OR (hieu qua)) - canh tranh van dang cong tac phan dau".
• Adding a wildcard symbol may retrieve word variants: toc ((hieu quang) OR (hieu qua)) - canh tranh van dang cong tac phan dau*.