Perhaps you should try some spelling variations:
tranh nghiem » trac nghiem, trach nhiem, trinh nghien
thuoc khach » thuoc khang, thuoc sach, thuc khac
trai nghiem » trac nghiem, thi nghiem
khach trai » khac trai, khanh tra, kham trai
sach tranh » canh tranh
khien hoc » nhiet hoc, dien hoc
thu sach » tu sach, thuat sach, thuoc sach

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( thuoc khach trai nghiem ngu hoc ) or ( thu sach tranh nghiem ((te hoc) or (khien hoc)) ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( thuoc khach trai nghiem ngu hoc ) OR ( thu sach tranh nghiem ((te hoc) OR (khien hoc)) )).
• Adding a wildcard symbol may retrieve word variants: (( thuoc khach trai nghiem ngu hoc ) or ( thu sach tranh nghiem ((te hoc) or (khien hoc)) ))*.