Perhaps you should try some spelling variations:
thong cong » trong cong, tong cong, thong thong
hieu lang » chieu sang, hieu quang, nhieu tang
chinh vat » chinh va, chinh dat, chinh viet
dung cong » dung trong
hoc hieu » hoc thieu, hoc hien, doc hieu
dan toan » van toan, dan than, manh toan
dan chan » dan gian, dan ca, van chat

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 - hanh chinh vat ((thong cong) or (dung cong)) ((dan toan) or (dan chan)) ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hieu lang - hanh chinh vat ((thong cong) OR (dung cong)) ((dan toan) OR (dan chan)) ban.
• Adding a wildcard symbol may retrieve word variants: hoc hieu lang - hanh chinh vat ((thong cong) or (dung cong)) ((dan toan) or (dan chan)) ban*.