Perhaps you should try some spelling variations:
trinh nhiet » trinh thiet, trinh nghien, trinh viet
nghiem quoc » nghiem duoc, nghiem nuoc, nghiep quoc
canh trinh » canh tranh, hanh trinh, canh tinh
sach trac » sach truc, sach tranh, sach tham
tu canh » thu canh, tu chanh, tu can
nhiet d » nhiet do, nhiet de, nhiet doi
tu sach » thu sach, su sach, te sach
d hoc » du hoc, ad hoc, de 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 canh trinh nhiet d hoc ) or ( tu sach trac nghiem quoc hoi ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu canh trinh nhiet d hoc ) OR ( tu sach trac nghiem quoc hoi )).
• Adding a wildcard symbol may retrieve word variants: (( tu canh trinh nhiet d hoc ) or ( tu sach trac nghiem quoc hoi ))*.