Perhaps you should try some spelling variations:
trinh thiet » trinh viet, trinh thi
trai nghiem » trac nghiem, thi nghiem
sach trai » sach tai, sach tranh, khach trai
hoc sach » hoc sinh, hoc anh
thiet te » thiet ke, thiet de, thiet yeu
toc sach » doc sach, thuoc sach, nuoc sach
nghiem d » nghiem de, nghiem do, nghiem _
hoc cac » hoc cao
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) OR (hoc cac)) trinh thiet te hoc ) or ( toc sach trai nghiem d hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( ((hoc sach) OR (hoc cac)) trinh thiet te hoc ) OR ( toc sach trai nghiem d hoc )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( ((hoc sach) OR (hoc cac)) trinh thiet te hoc ) or ( toc sach trai nghiem d hoc ))".
• Adding a wildcard symbol may retrieve word variants: (( ((hoc sach) OR (hoc cac)) trinh thiet te hoc ) or ( toc sach trai nghiem d hoc ))*.