Perhaps you should try some spelling variations:
sach trinh » sach tranh, hanh trinh, sach kinh
trinh nghe » trinh nghien, trinh he, trinh nha
trac nghe » thai nghe, cac nghe, mac nghe
duoc hoc » quoc hoi
nghe tai » ngheo tai, nghe thai, nghe tan
su khac » vu khac, se khac, bui khac
su sach » so sach, vu sach
tai hoc » thai hoc, dai hoc, bai hoc

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

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