Perhaps you should try some spelling variations:
tranh nghiem » trac nghiem, trach nhiem, trinh nghien
thuc nghiem » trac nghiem
sanh tranh » canh tranh, sach tranh, lanh tranh
nghiem _ » nghiem d, nghiem h, nghiem y
so sanh » do sanh
co sach » bo sach, cuon sach, hoc sach
de hoc » te hoc, du hoc, dien 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 sanh tranh nghiem _ hoc ) or ( co sach ((thi nghiem) OR (thuc nghiem)) de hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( so sanh tranh nghiem _ hoc ) OR ( co sach ((thi nghiem) OR (thuc nghiem)) de hoc ))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( so sanh tranh nghiem _ hoc ) or ( co sach ((thi nghiem) OR (thuc nghiem)) de hoc ))*".