Perhaps you should try some spelling variations:
hieu lang » chieu sang, hieu quang, nhieu tang
dung cong » dung trong
hoc hieu » hoc thieu, hoc hien, doc hieu
huong va » thuong va, luong va, muong va
duong va » duong van, dung va, luong va
cong dan » cong san, cong tan, huong dan
dan toan » van toan, dan than, manh toan
toan tap » toan ban

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 - manh ((huong va) or (duong va)) dung cong dan toan tap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hieu lang - manh ((huong va) OR (duong va)) dung cong dan toan tap.
• Adding a wildcard symbol may retrieve word variants: hoc hieu lang - manh ((huong va) or (duong va)) dung cong dan toan tap*.