Perhaps you should try some spelling variations:
trai nghiem » trac nghiem, thi nghiem
tham nghiem » trac nghiem, thuc nghiem, thi nghiem
sach tham » sach nha
nghiem ye » nghiem de, nghiem te, nghiem ve
nghiem do » nghiem d, nghiem de, nghiem duoc
hoc sach » hoc sinh, hoc cac, hoc anh
tu khac » vu khac, su khac, ta khac
ye hoc » y hoc, te hoc, de hoc
do hoc » co hoc, do hoa, du hoc

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( hoc sach tham nghiem ye hoc ) or ( tu khac trai nghiem do hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( hoc sach tham nghiem ye hoc ) OR ( tu khac trai nghiem do hoc ))*.