Perhaps you should try some spelling variations:
trai nghiem » trac nghiem, thi nghiem
trach nhiem » trac nghiem
cong trach » thong trach, cong tac, cong trinh
nhiem thuc » nghiem thuc, nghiem thuoc, nghiep thuc
sach trai » sach tai, sach tranh, khach trai
thuc hoc » phuc hoc, thu hoc, thuc uoc
nghiem d » nghiem de, nghiem _, nghiem h
tu sach » thu sach, su sach, te sach
d hoc » du hoc, ad hoc, de hoc

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( thu cong trach nhiem thuc hoc ) or ( tu sach trai nghiem d hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( thu cong trach nhiem thuc hoc ) OR ( tu sach trai nghiem d hoc )).
• Adding a wildcard symbol may retrieve word variants: (( thu cong trach nhiem thuc hoc ) or ( tu sach trai nghiem d hoc ))*.