Perhaps you should try some spelling variations:
trinh nghien » trinh nghe, trinh dien
trinh thiet » trinh viet, trinh thi
hang trinh » hanh trinh, thanh trinh, trang trinh
thiet de » thiet ke, nhiet de, thiet yeu
thu sach » tu sach, thuat sach, thuoc sach
ly hang » ly quang
dau hoc » dai hoc, du hoc, dan hoc
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 hang trinh thiet de hoc ) OR ( thu sach ((trinh nghien) OR (kinh nghiem)) dau hoc ))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( ly hang trinh thiet de hoc ) or ( thu sach ((trinh nghien) OR (kinh nghiem)) dau hoc ))~".
• Adding a wildcard symbol may retrieve word variants: (( ly hang trinh thiet de hoc ) or ( thu sach ((trinh nghien) OR (kinh nghiem)) dau hoc ))*.