Perhaps you should try some spelling variations:
tranh nghiep » doanh nghiep, trinh nghien, trinh nghe
trinh thiet » trinh viet, trinh thi
hang trinh » hanh trinh, thanh trinh, trang trinh
thuoc sach » hoc sach, nuoc sach, thuat sach
thiet de » thiet ke, nhiet de, thiet yeu
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.

• Performing a fuzzy search may retrieve terms with similar spellings: (( ly hang trinh thiet de hoc ) or ( thuoc sach ((tranh nghiep) OR (trac nghiem)) dau hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( ly hang trinh thiet de hoc ) OR ( thuoc sach ((tranh nghiep) OR (trac nghiem)) dau hoc )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( ly hang trinh thiet de hoc ) or ( thuoc sach ((tranh nghiep) OR (trac nghiem)) dau hoc ))".
• Adding a wildcard symbol may retrieve word variants: (( ly hang trinh thiet de hoc ) or ( thuoc sach ((tranh nghiep) OR (trac nghiem)) dau hoc ))*.