Perhaps you should try some spelling variations:
sach trach » sach tranh, sat trach
tinh nhiet » trinh nhiet, tinh thiet, trinh thiet
nhiem quoc » nghiem quoc, nhiem cuoc, nghiem duoc
canh tinh » hanh tinh, manh tinh, canh tranh
sach truc » cach thuc, sach tren, sach thu
nhiet do » nhiet doi, nhiet dong, nhiet hoc
tu canh » thu canh, tu chanh, tu can
do hoc » co hoc, do hoa, 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 canh tinh nhiet do hoc ) or ( tu ((sach trach) OR (sach truc)) nhiem quoc hoi ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu canh tinh nhiet do hoc ) OR ( tu ((sach trach) OR (sach truc)) nhiem quoc hoi )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( tu canh tinh nhiet do hoc ) or ( tu ((sach trach) OR (sach truc)) nhiem quoc hoi ))".
• Adding a wildcard symbol may retrieve word variants: (( tu canh tinh nhiet do hoc ) or ( tu ((sach trach) OR (sach truc)) nhiem quoc hoi ))*.