Perhaps you should try some spelling variations:
nhung cong » dung cong, thong cong, nhung don
theo hieu » theo chieu, theo tieu, thien hieu
hieu lang » chieu sang, hieu quang, nhieu tang
hang cong » dang cong, hang nong, bang cong
anh dung » anh dong, anh huong, sach dung
toan cao » toan tap
toan ban » van ban

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