Perhaps you should try some spelling variations:
thieu xanh » chieu xanh, thien anh, thien danh
hieu manh » chieu xanh, hieu nganh, dieu hanh
cang hang » cang thang, hang hang, nang hang
dang cong » dung cong
cong tap » cuong tap, cong tac, cong tan
tap toan » tap doan, tap quan, bai toan
toan cau » toan cao, toan ban, toan tap
hang ca » hang va, nang cao, hang tai
ca dang » cao dang, cua dang, cac dang

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)) - cang hang ca dang cong tap toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((thieu xanh) OR (hieu manh)) - cang hang ca dang cong tap toan cau.
• Adding a wildcard symbol may retrieve word variants: hoc ((thieu xanh) or (hieu manh)) - cang hang ca dang cong tap toan cau*.