Perhaps you should try some spelling variations:
che thuoc » nha thuoc, cay thuoc, cua thuoc
canh tinh » hanh tinh, manh tinh, canh tranh
tu sach » thu sach, su sach, tu cach
du canh » du hanh, do canh, luc canh
te sach » toc sach
re nghe » ve nghe, te nghe
nghe vi » nghe va, nghe noi
vi hoc » li hoc, va 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 sach) OR (te sach)) re nghe vi hoc ) or ( du canh tinh ((che thuoc) or (che do)) hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( ((tu sach) OR (te sach)) re nghe vi hoc ) OR ( du canh tinh ((che thuoc) OR (che do)) hoc )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( ((tu sach) OR (te sach)) re nghe vi hoc ) or ( du canh tinh ((che thuoc) or (che do)) hoc ))".
• Adding a wildcard symbol may retrieve word variants: (( ((tu sach) OR (te sach)) re nghe vi hoc ) or ( du canh tinh ((che thuoc) or (che do)) hoc ))*.