Perhaps you should try some spelling variations:
hien xanh » hien hanh, hien nhanh, chieu xanh
tranh cua » doanh cua, manh cua
dang cong » dung cong
tang cua » mang cua, hang cua, tang luan
cong tap » cuong tap, cong tac, cong tan
tap toan » tap doan, tap quan, bai toan
toan ban » van ban

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

• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hien xanh - hanh ((tang cua) OR (tranh cua)) dang cong tap toan ban~.
• Adding a wildcard symbol may retrieve word variants: hoc hien xanh - hanh ((tang cua) or (tranh cua)) dang cong tap toan ban*.