Perhaps you should try some spelling variations:
nhung cong » thong cong, hang cong, nhung don
hieu lang » chieu sang, hieu quang, nhieu tang
trung cua » truong cua, trung tuan, trung cap
dung cong » dung trong
tac toan » tap toan, tam toan, hach toan
toan tap » toan ban
ho hieu » ho chieu, hoi hieu, nho hieu

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

• Performing a fuzzy search may retrieve terms with similar spellings: ho hieu lang - hanh ((trung cua) or (trung tam)) ((nhung cong) or (dung cong)) tac toan tap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ho hieu lang - hanh ((trung cua) OR (trung tam)) ((nhung cong) OR (dung cong)) tac toan tap.
• Adding a wildcard symbol may retrieve word variants: ho hieu lang - hanh ((trung cua) or (trung tam)) ((nhung cong) or (dung cong)) tac toan tap*.