Perhaps you should try some spelling variations:
trinh nghien » trinh nghe, kinh nghiem, trinh thiet
trach nhiem » trac nghiem
sach trach » sach tranh, sach truc, sat trach
nhiem dai » nhien dai, nhiem tai, nghiep dai
thu sach » tu sach, thuat sach, thuoc sach
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 dai hoc ) or ( so sach ((trinh nghien) or (doanh nghiep)) vu hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( thu sach trach nhiem dai hoc ) OR ( so sach ((trinh nghien) OR (doanh nghiep)) vu hoc )).
• Adding a wildcard symbol may retrieve word variants: (( thu sach trach nhiem dai hoc ) or ( so sach ((trinh nghien) or (doanh nghiep)) vu hoc ))*.