Perhaps you should try some spelling variations:
trinh nghien » trinh nghe, kinh nghiem, trinh thiet
nghiem duoc » nghiem thuoc, nghe duoc
sach trac » sach truc, sach tranh, sach tham
nghien de » nghiem de, nghiep ke, nghiem d
duoc hoc » quoc hoi
thu canh » thuc hanh, thu ban, thu hang
te sach » toc sach
de hoc » te hoc, du hoc, dien hoc

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: (( te sach trac nghiem duoc hoc ) OR ( ((thu canh) OR (thu cong)) trinh nghien de hoc ))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( te sach trac nghiem duoc hoc ) or ( ((thu canh) OR (thu cong)) trinh nghien de hoc ))~".
• Adding a wildcard symbol may retrieve word variants: (( te sach trac nghiem duoc hoc ) or ( ((thu canh) OR (thu cong)) trinh nghien de hoc ))*.