Perhaps you should try some spelling variations:
hieu quang » thieu quang, hieu quan, hieu qua
chiet tach » chieu sach
hanh nhanh » hanh nhan, nhanh thanh, thanh thanh
quang dung » quang trung, ung dung, cuong dung
hieu lang » chieu sang, nhieu tang, hieu van
dung cong » dung trong
van thanh » ban thanh, van tuan
thanh ban » thanh san, thanh van, thanh bac
cong van » cong vang, cong san, song van

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))) or (chiet tach)) - hanh nhanh quang dung cong van thanh ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((((hieu lang) OR (hieu quang))) OR (chiet tach)) - hanh nhanh quang dung cong van thanh ban.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((((hieu lang) OR (hieu quang))) or (chiet tach)) - hanh nhanh quang dung cong van thanh ban".
• Adding a wildcard symbol may retrieve word variants: hoc ((((hieu lang) OR (hieu quang))) or (chiet tach)) - hanh nhanh quang dung cong van thanh ban*.