Perhaps you should try some spelling variations:
trach nhiem » trac nghiem
sach trinh » hanh trinh, sach kinh, sach tren
sach tranh » canh tranh
hat trach » sat trach, hai trac
nghien du » nghiep du, nghien cuu, nghiem dau
nhiem tu » nhiem thuc, nhiem huu, nghiem su
tuc hat » tuc hai, tu hat, tuc ha
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: (( tuc hat trach nhiem tu hoc ) or ( te ((sach trinh) OR (sach tranh)) nghien du hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tuc hat trach nhiem tu hoc ) OR ( te ((sach trinh) OR (sach tranh)) nghien du hoc ))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( tuc hat trach nhiem tu hoc ) or ( te ((sach trinh) OR (sach tranh)) nghien du hoc ))*".