Perhaps you should try some spelling variations:
trinh nghien » trinh nghe, kinh nghiem, trinh thiet
hanh trinh » hanh chinh
nghien di » nghiep di, nghiep dai, nghiem vi
tranh thi » tranh thai, tran thi, trinh thi
tu hanh » du hanh, lu hanh, thuc hanh
tu canh » thu canh, tu chanh, tu can
diu hoc » du hoc, lieu hoc, dich hoc
dia hoc » dia oc, dich hoc, dien hoc
di hoc » dai hoc, li 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: (( tu hanh trinh nghien di hoc ) or ( tu canh tranh thi ((diu hoc) or (dia hoc)) ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu hanh trinh nghien di hoc ) OR ( tu canh tranh thi ((diu hoc) OR (dia hoc)) )).
• Adding a wildcard symbol may retrieve word variants: (( tu hanh trinh nghien di hoc ) or ( tu canh tranh thi ((diu hoc) or (dia hoc)) ))*.