Perhaps you should try some spelling variations:
khong trong » khoang trong, thong trong, phong trong
hieu xanh » chieu xanh, hieu manh, hieu nganh
tranh cua » doanh cua, manh cua
cua khong » hua khong, cua phuong, cua thuong
trong van » trong cac
doc hieu » toc thieu, hoc thieu, hoc hien
phan cau » phan dau, phan tu, phan lap
phan cac » nhan cach, phan dau, phan lap

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: doc hieu xanh - canh tranh cua khong trong van ((phan cau) OR (phan cac))~.
• Adding a wildcard symbol may retrieve word variants: doc hieu xanh - canh tranh cua khong trong van ((phan cau) or (phan cac))*.