Perhaps you should try some spelling variations:
thieu xanh » chieu xanh, hieu manh, thien anh
hanh tranh » canh tranh, hanh trinh, hanh trang
tranh chua » tranh cua, trinh chuan, tranh chap
hoc thieu » toc thieu, hoc hien
dung cong » dung trong
bang song » nang song
toan cau » toan ban, toan tap, toan tai
toan cao » toan ban, toan tap

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 thieu xanh - hanh tranh chua ((dung cong) OR (bang song)) dan ((toan cau) OR (toan cao))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc thieu xanh - hanh tranh chua ((dung cong) or (bang song)) dan ((toan cau) OR (toan cao))~".
• Adding a wildcard symbol may retrieve word variants: hoc thieu xanh - hanh tranh chua ((dung cong) or (bang song)) dan ((toan cau) OR (toan cao))*.