Perhaps you should try some spelling variations:
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 » do canh, luc canh, thu canh
du hanh » dieu hanh, duy khanh, luu hanh
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) OR (du hanh)) 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) OR (du hanh)) trinh che duoc hoc )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( tu sach re nghe vi hoc ) or ( ((du canh) OR (du hanh)) trinh che duoc hoc ))".
• Adding a wildcard symbol may retrieve word variants: (( tu sach re nghe vi hoc ) or ( ((du canh) OR (du hanh)) trinh che duoc hoc ))*.