Perhaps you should try some spelling variations:
hieu quang » thieu quang, hieu quan, hieu qua
nhung cong » dung cong, thong cong, hang cong
hieu lang » chieu sang, nhieu tang, hieu van
trung cua » truong cua, trung tuan, dung cua
trung cap » truong cao, trung tam
cong tan » cong tac, cong san, cong thanh
tran tan » tran tuan, tran van, tran thanh

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