Perhaps you should try some spelling variations:
trinh nghe » trinh nghien, trinh he, trinh nha
cac trinh » cac tinh, lap trinh, cac thanh
nghe dia » nghe di, nghe dien, nghe giai
nghe vi » nghe va, nghe noi
tu sach » thu sach, te sach, tu cach
su sach » so sach, vu sach
vi hoc » li hoc, va hoc

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( tu cac trinh nghe vi hoc ) or ( ((tu sach) OR (su sach)) trinh nghe dia oc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu cac trinh nghe vi hoc ) OR ( ((tu sach) OR (su sach)) trinh nghe dia oc )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( tu cac trinh nghe vi hoc ) or ( ((tu sach) OR (su sach)) trinh nghe dia oc ))".
• Adding a wildcard symbol may retrieve word variants: (( tu cac trinh nghe vi hoc ) or ( ((tu sach) OR (su sach)) trinh nghe dia oc ))*.