Perhaps you should try some spelling variations:
hien xanh » hien hanh, hien nhanh, chieu xanh
hang cong » dang cong, hang nong, bang cong
trang va » hang va
tran van » luan van
cong tai » cong thai, cong tac, dong tai
tai phan » tai thanh, tai phong, tai ngan
phan dau » phan tu, hang dau

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc hien xanh - canh ((trang va) or (tran van)) hang cong tai phan dau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hien xanh - canh ((trang va) OR (tran van)) hang cong tai phan dau.
• Adding a wildcard symbol may retrieve word variants: hoc hien xanh - canh ((trang va) or (tran van)) hang cong tai phan dau*.