Perhaps you should try some spelling variations:
hanh trinh » canh tranh, hanh chinh
trinh nghe » trinh nghien, trinh he, trinh nha
sach trac » sach truc, sach tranh, sach tham
so hanh » so sanh, so danh, co hanh
so sach » so sanh, bo sach, co sach
su hoc » so hoc, su ho, su hoa
tu hoc » te hoc
de hoc » te hoc, dien hoc
du hoc » duoc hoc

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

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