Perhaps you should try some spelling variations:
trinh nghien » trinh nghe, kinh nghiem, trinh thiet
trach nhiem » trac nghiem
hanh trinh » canh tranh, hanh chinh
sach trach » sach tranh, sach truc, sat trach
nghien de » nghiem de, nghiep ke, nghiem d
nhiem dan » nghiem ban, nghiem van, nghiem dau
du hanh » dieu hanh, duy khanh, luu hanh
tu sach » thu sach, su sach, te sach
dan hoc » van hoc, dan toc, dai hoc
de hoc » te hoc, du hoc, dien hoc

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( du hanh trinh nghien de hoc ) or ( tu sach trach nhiem dan hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( du hanh trinh nghien de hoc ) OR ( tu sach trach nhiem dan hoc )).
• Adding a wildcard symbol may retrieve word variants: (( du hanh trinh nghien de hoc ) or ( tu sach trach nhiem dan hoc ))*.