Perhaps you should try some spelling variations:
thieu xanh » chieu xanh, thien anh, thien danh
hieu manh » chieu xanh, hieu nganh, dieu hanh
hang nang » chang nang, hang nong, hang hang
cao hang » cao dang, cao tang, cao bang
cong tan » cong tac, cong thanh, cong ty
cong san » cong tac
toan cao » toan ban, toan tap

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((thieu xanh) or (hieu manh)) - hang nang cao hang ((cong tan) OR (cong san)) toan cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((thieu xanh) OR (hieu manh)) - hang nang cao hang ((cong tan) OR (cong san)) toan cao.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((thieu xanh) or (hieu manh)) - hang nang cao hang ((cong tan) OR (cong san)) toan cao".
• Adding a wildcard symbol may retrieve word variants: hoc ((thieu xanh) or (hieu manh)) - hang nang cao hang ((cong tan) OR (cong san)) toan cao*.