Perhaps you should try some spelling variations:
hieu quang » thieu quang, hieu quan, hieu qua
trung tuan » trung thanh, trung tam, tran tuan
dang thanh » dong thanh, hoang thanh, quang thanh
truong ca » truong cao, truong va, trong ca
dung cong » dung trong
dang hanh » ban hanh, dang van, dang hung
doc hieu » toc thieu, hoc thieu, hoc hien

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 quang - hanh ((trung tuan) or (truong ca)) dung cong ((dang thanh) OR (dang hanh)) van~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu quang - hanh ((trung tuan) OR (truong ca)) dung cong ((dang thanh) OR (dang hanh)) van.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc hieu quang - hanh ((trung tuan) or (truong ca)) dung cong ((dang thanh) OR (dang hanh)) van".
• Adding a wildcard symbol may retrieve word variants: doc hieu quang - hanh ((trung tuan) or (truong ca)) dung cong ((dang thanh) OR (dang hanh)) van*.