Perhaps you should try some spelling variations:
hien xanh » hien hanh, hien nhanh, chieu xanh
tranh cua » doanh cua, manh cua
bang song » nang song
bean song » phan song, gian song, ven song
ban song » ban cong, ban tong, can song
dan than » dan chan, ban than, van than
than cao » toan cao, thai cao, than cap

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 - canh tranh cua ((((ban song) OR (bang song))) OR (bean song)) dan than cao~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc hien xanh - canh tranh cua ((((ban song) OR (bang song))) or (bean song)) dan than cao~".
• Adding a wildcard symbol may retrieve word variants: hoc hien xanh - canh tranh cua ((((ban song) OR (bang song))) or (bean song)) dan than cao*.