Perhaps you should try some spelling variations:
tren nghiep » trien nghiep, tron nghien
sach trai » sach tai, sach tranh, khach trai
sach tren » sach tien, sach tranh
nghiep du » nghiep dau, nghiep tu, nghiep di
te sach » toc sach
so sach » so sanh, bo sach, co sach
du hoc » tu hoc, duoc hoc

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( te sach trai ((nghiep va) OR (nghiep vu)) hoc ) or ( so sach tren nghiep du hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( te sach trai ((nghiep va) OR (nghiep vu)) hoc ) OR ( so sach tren nghiep du hoc ))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( te sach trai ((nghiep va) OR (nghiep vu)) hoc ) or ( so sach tren nghiep du hoc ))*".