Perhaps you should try some spelling variations:
canh trinh » canh tranh, hanh trinh, canh tinh
trinh che » trinh he, trinh cho, trinh chu
che duoc » che thuoc, che do, te duoc
duoc hoc » quoc hoi
tu sach » thu sach, su sach, te sach
sach re » sach de, sach tren, sach kem
re nghe » ve nghe, te nghe
nghe vi » nghe va, nghe noi
du canh » du hanh, do canh, luc canh
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 re nghe vi hoc ) or ( du canh trinh che duoc hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu sach re nghe vi hoc ) OR ( du canh trinh che duoc hoc )).
• Adding a wildcard symbol may retrieve word variants: (( tu sach re nghe vi hoc ) or ( du canh trinh che duoc hoc ))*.