Perhaps you should try some spelling variations:
thanh trung » thanh tung
hieu quang » thieu quang, hieu quan, hieu qua
duong cong » dung cong, luong cong, duong trong
hieu lang » chieu sang, nhieu tang, hieu van
trung cua » truong cua, trung tuan, trung cap
dong cong » dung cong, dang cong, cong cong
tan toan » tan tran, tap toan, van toan
toan cau » toan cao, toan ban, toan tap

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) OR (hieu quang)) - thanh trung cua ((dong cong) or (duong cong)) tan toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ho ((hieu lang) OR (hieu quang)) - thanh trung cua ((dong cong) OR (duong cong)) tan toan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "ho ((hieu lang) OR (hieu quang)) - thanh trung cua ((dong cong) or (duong cong)) tan toan cau".
• Adding a wildcard symbol may retrieve word variants: ho ((hieu lang) OR (hieu quang)) - thanh trung cua ((dong cong) or (duong cong)) tan toan cau*.