Perhaps you should try some spelling variations:
trinh thiet » trinh viet, trinh thi
sach trinh » sach tranh, hanh trinh, sach kinh
nghiem de » nghiem d, nghiem do, nghiem ve
nghiem te » nghiem ve, nghiem tien, nghiem tren
thiet dai » thiet hai, thuyet dai, hien dai
toc pham » tac pham, toc cham, toi pham
tu sach » thu sach, su sach, te sach

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) OR (nghiem te)) 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) OR (nghiem te)) hoc ) OR ( tu sach trinh thiet dai hoc )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( toc pham van ((nghiem de) OR (nghiem te)) hoc ) or ( tu sach trinh thiet dai hoc ))".
• Adding a wildcard symbol may retrieve word variants: (( toc pham van ((nghiem de) OR (nghiem te)) hoc ) or ( tu sach trinh thiet dai hoc ))*.