Perhaps you should try some spelling variations:
tranh nghiep » trinh nghien, trac nghiem, trinh nghe
trach nhiem » trac nghiem
sach trach » sach tranh, sach truc, sat trach
nhiem bai » nhiem tai, nghiem ban, nghiep bai
thu sach » tu sach, thuat sach, thuoc sach
bai hoc » dai hoc
so sach » so sanh, bo sach, co sach
vu hoc » tu hoc, va hoc, du hoc

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( thu sach trach nhiem bai hoc ) or ( so sach ((tranh nghiep) OR (doanh nghiep)) vu hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( thu sach trach nhiem bai hoc ) OR ( so sach ((tranh nghiep) OR (doanh nghiep)) vu hoc )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( thu sach trach nhiem bai hoc ) or ( so sach ((tranh nghiep) OR (doanh nghiep)) vu hoc ))".
• Adding a wildcard symbol may retrieve word variants: (( thu sach trach nhiem bai hoc ) or ( so sach ((tranh nghiep) OR (doanh nghiep)) vu hoc ))*.