Perhaps you should try some spelling variations:
khanh trinh » hanh trinh, thanh trinh, nhanh tinh
trinh ghep » trinh phap, trinh nhap, trinh nghien
trinh nghe » trinh nghien, trinh nha
trinh he » trinh han, trinh hoa, trinh thi
co hanh » co thanh, co phanh, co anh
nghe du » nghe duc, nghe xu, nghe di
tu hoc » te hoc
du hoc » duoc hoc

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: (( co hanh ((trinh ghep) OR (trinh he)) tu hoc ) OR ( duy khanh trinh nghe du hoc ))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( co hanh ((trinh ghep) OR (trinh he)) tu hoc ) or ( duy khanh trinh nghe du hoc ))~".
• Adding a wildcard symbol may retrieve word variants: (( co hanh ((trinh ghep) OR (trinh he)) tu hoc ) or ( duy khanh trinh nghe du hoc ))*.