Perhaps you should try some spelling variations:
trinh nghien » trinh nghe, kinh nghiem, trinh thiet
trai nghiem » trac nghiem
thi nghiem » thuc nghiem
canh trinh » canh tranh, hanh trinh, canh tinh
nghien o » nghiep o, nghiep so, nghiep co
te sach » toc sach
d hoc » du hoc, ad hoc, de hoc
o hoc » co hoc, mo hoc, so hoc

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( te sach ((trai nghiem) or (thi nghiem)) d hoc ) or ( luc canh trinh nghien o hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( te sach ((trai nghiem) OR (thi nghiem)) d hoc ) OR ( luc canh trinh nghien o hoc )).
• Adding a wildcard symbol may retrieve word variants: (( te sach ((trai nghiem) or (thi nghiem)) d hoc ) or ( luc canh trinh nghien o hoc ))*.