Perhaps you should try some spelling variations:
hieu quang » thieu quang, hieu quan, hieu qua
hieu lang » chieu sang, nhieu tang, hieu van
cong tan » cong tac, cong san, cong thanh
tan toan » tan tran, tap toan, van toan
toan tap » toan ban
vi dung » va dung, vi dong, viet dung
vi ung » va ung, vi luong, vi trung

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)) - canh tranh ((vi dung) or (vi ung)) cong tan toan tap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: theo ((hieu lang) OR (hieu quang)) - canh tranh ((vi dung) OR (vi ung)) cong tan toan tap.
• The words AND, OR and NOT may confuse the search; try adding quotes: "theo ((hieu lang) OR (hieu quang)) - canh tranh ((vi dung) or (vi ung)) cong tan toan tap".
• Adding a wildcard symbol may retrieve word variants: theo ((hieu lang) OR (hieu quang)) - canh tranh ((vi dung) or (vi ung)) cong tan toan tap*.