Perhaps you should try some spelling variations:
trinh thiet » trinh viet, trinh thi
van nghiem » van nghe, van nghia, quang nghiem
sach trinh » sach tranh, hanh trinh, sach kinh
nghiem de » nghiem d, nghiem do, nghiem te
thiet dai » thiet hai, thuyet dai, hien dai
toc pham » tac pham, toc cham, toi pham
tu sach » thu sach, su sach, te sach
de hoc » te hoc, du hoc, dien hoc

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( toc pham van nghiem de hoc ) or ( tu sach trinh thiet dai hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( toc pham van nghiem de hoc ) OR ( tu sach trinh thiet dai hoc )).
• Adding a wildcard symbol may retrieve word variants: (( toc pham van nghiem de hoc ) or ( tu sach trinh thiet dai hoc ))*.