Perhaps you should try some spelling variations:
hieu quang » thieu quang, hieu quan, diep quang
thanh tran » thanh trang, thanh toan, thanh tra
duong cong » dung cong, luong cong, duong trong
van duong » van dong, van dung, van phong
tran van » luan van
tap toan » tap doan, tap quan
bai toan » bai tap

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

• Performing a fuzzy search may retrieve terms with similar spellings: theo ((hieu quang) or (hieu qua)) - thanh tran van duong cong ((tap toan) or (bai toan)) cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: theo ((hieu quang) OR (hieu qua)) - thanh tran van duong cong ((tap toan) OR (bai toan)) cau.
• Adding a wildcard symbol may retrieve word variants: theo ((hieu quang) or (hieu qua)) - thanh tran van duong cong ((tap toan) or (bai toan)) cau*.