Perhaps you should try some spelling variations:
tranh nhiem » trach nhiem, trinh nhiet
trinh thiet » trinh viet, trinh thi
hanh trinh » hanh chinh
thiet duoc » chet duoc, hiem duoc, thuat duoc
nhiem ad » nhiem mau, nhiem tai, nhiem va
duoc hoc » quoc hoi
tu canh » thu canh, tu chanh, tu can
tu hanh » du hanh, lu hanh, thuc hanh

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( tu canh tranh nhiem ad hoc ) or ( tu hanh trinh thiet duoc hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu canh tranh nhiem ad hoc ) OR ( tu hanh trinh thiet duoc hoc ))*.