Perhaps you should try some spelling variations:
sach tranh » canh tranh
tra nghiem » trac nghiem, trai nghiem, thi nghiem
nghiem son » nghiem song, nghiem mon, nghiem cong
khanh tra » thanh tra, khanh trach, khanh hoa
nghiem de » nghiem d, nghiem te, nghiem ve
vu khanh » vu thanh, van khanh, duy khanh
vu sach » vu bach, su sach, vu khach
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: (( vu khanh tra nghiem de hoc ) or ( vu sach tranh ((nghiem son) or (nghiem ngu)) hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( vu khanh tra nghiem de hoc ) OR ( vu sach tranh ((nghiem son) OR (nghiem ngu)) hoc )).
• Adding a wildcard symbol may retrieve word variants: (( vu khanh tra nghiem de hoc ) or ( vu sach tranh ((nghiem son) or (nghiem ngu)) hoc ))*.