Perhaps you should try some spelling variations:
trinh thiet » trinh viet, trinh thi
trai nghiem » trac nghiem
sach trinh » sach tranh, hanh trinh, sach kinh
thi nghiem » thuc nghiem
hoc sach » hoc sinh, hoc cac, hoc anh
thiet bi » thiet ke
te sach » toc sach
bi hoc » bai hoc, li hoc, vi hoc
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: (( hoc sach trinh thiet bi hoc ) or ( te sach ((trai nghiem) OR (thi nghiem)) d hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( hoc sach trinh thiet bi hoc ) OR ( te sach ((trai nghiem) OR (thi nghiem)) d hoc )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( hoc sach trinh thiet bi hoc ) or ( te sach ((trai nghiem) OR (thi nghiem)) d hoc ))".
• Adding a wildcard symbol may retrieve word variants: (( hoc sach trinh thiet bi hoc ) or ( te sach ((trai nghiem) OR (thi nghiem)) d hoc ))*.