Perhaps you should try some spelling variations:
hieu quang » thieu quang, hieu quan, hieu qua
hieu lang » chieu sang, nhieu tang, hieu van
trung cap » truong cao
hang cong » dang cong, hang nong, bang cong
cong tac » cong ty
tac va » tac da, tac xa, tuc va
va ban » van ban, va bai, va bao

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((hieu lang) OR (hieu quang)) - thanh ((trung cap) or (trung tam)) hang cong tac va ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((hieu lang) OR (hieu quang)) - thanh ((trung cap) OR (trung tam)) hang cong tac va ban.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((hieu lang) OR (hieu quang)) - thanh ((trung cap) or (trung tam)) hang cong tac va ban".
• Adding a wildcard symbol may retrieve word variants: hoc ((hieu lang) OR (hieu quang)) - thanh ((trung cap) or (trung tam)) hang cong tac va ban*.