Perhaps you should try some spelling variations:
tham nghiem » thuc nghiem, thi nghiem, thu nghiem
tranh nghe » trinh nghe, anh nghe, hanh nghe
nghe duoc » nghiem duoc, nghe nuoi, che duoc
duoc hoc » quoc hoi
so sach » so sanh, bo sach, co sach
dau hoc » dai hoc, du hoc, dan hoc
so canh » so sanh, bo canh, so danh

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( so sach ((tham nghiem) or (trac nghiem)) dau hoc ) or ( so canh tranh nghe duoc hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( so sach ((tham nghiem) OR (trac nghiem)) dau hoc ) OR ( so canh tranh nghe duoc hoc )).
• Adding a wildcard symbol may retrieve word variants: (( so sach ((tham nghiem) or (trac nghiem)) dau hoc ) or ( so canh tranh nghe duoc hoc ))*.