Perhaps you should try some spelling variations:
trinh nghien » trinh nghe, kinh nghiem, trinh thiet
trach nhiem » trac nghiem
sach trinh » sach tranh, hanh trinh, sach kinh
hat trach » sat trach, hai trac
nghien du » nghiep du, nghien cuu, nghiem dau
nhiem tu » nhiem thuc, nhiem huu, nghiem su
te sach » toc sach
tu hat » tu phat, tuc hat, tu bat
tu hoc » te hoc
du 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: (( tu hat trach nhiem tu hoc ) or ( te sach trinh nghien du hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu hat trach nhiem tu hoc ) OR ( te sach trinh nghien du hoc ))*.