Perhaps you should try some spelling variations:
trinh thiet » trinh viet, trinh thi
sach trinh » hanh trinh, sach kinh, sach tren
sach tranh » canh tranh
nghien dai » nghiep dai, nhien dai, hien dai
anh trinh » hanh trinh, anh tinh, thanh trinh
thiet de » thiet ke, nhiet de, thiet yeu
ly anh » le anh
de hoc » te hoc, du hoc, dien hoc

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

• If you are trying to use Boolean operators, they must be ALL CAPS: (( ly anh trinh thiet de hoc ) OR ( thu ((sach trinh) OR (sach tranh)) nghien dai hoc ))~.
• Adding a wildcard symbol may retrieve word variants: (( ly anh trinh thiet de hoc ) or ( thu ((sach trinh) or (sach tranh)) nghien dai hoc ))*.