Perhaps you should try some spelling variations:
trinh nghien » trinh nghe, kinh nghiem, trinh thiet
sanh trinh » hanh trinh, anh trinh, sinh trinh
sach trinh » sach tranh, hanh trinh, sach kinh
nghien tu » nghiep tu, nghien cuu, nghiep vu
so sanh » do sanh
vu sach » vu bach, su sach, vu khach
tu hoc » te hoc
o hoc » mo hoc, so hoc, y hoc

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

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