Perhaps you should try some spelling variations:
hieu quang » thieu quang, hieu quan, hieu qua
nhung cong » dung cong, thong cong, hang cong
trinh toan » tinh toan, thanh toan, trinh han
doc hieu » toc thieu, hoc thieu, hoc hien
trung va » truong va, trang va, trung tam
trung ha » trung hoc, trung tam, trung cap
toan ban » van ban

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 - thanh ((trung va) or (trung ha)) nhung cong trinh toan ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu quang - thanh ((trung va) OR (trung ha)) nhung cong trinh toan ban.
• Adding a wildcard symbol may retrieve word variants: doc hieu quang - thanh ((trung va) or (trung ha)) nhung cong trinh toan ban*.