Perhaps you should try some spelling variations:
trinh toan » tinh toan, thanh toan, trinh han
trinh tai » trinh tu, trinh han, chinh tai
canh tran » canh tranh, hanh trang, banh trang
tu hanh » du hanh, lu hanh, thuc hanh
tu canh » thu canh, tu chanh, tu can
diu hoc » lieu hoc, dich hoc, dien hoc
dia hoc » dia oc, dich hoc, dien hoc
du hoc » tu 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 hanh ((trinh tai) OR (trinh toan)) du hoc ) or ( tu canh tran thi ((diu hoc) or (dia hoc)) ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu hanh ((trinh tai) OR (trinh toan)) du hoc ) OR ( tu canh tran thi ((diu hoc) OR (dia hoc)) )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( tu hanh ((trinh tai) OR (trinh toan)) du hoc ) or ( tu canh tran thi ((diu hoc) or (dia hoc)) ))".
• Adding a wildcard symbol may retrieve word variants: (( tu hanh ((trinh tai) OR (trinh toan)) du hoc ) or ( tu canh tran thi ((diu hoc) or (dia hoc)) ))*.