Perhaps you should try some spelling variations:
tinh nghien » trinh nghien, kinh nghiem, tinh nghe
kinh nghien » kinh nghiem, trinh nghien, kinh hien
canh tinh » hanh tinh, manh tinh, canh tranh
nghien ad » nghiem d, nghien o, nghiep a
tu canh » thu canh, tu chanh, tu can
so sach » bo sach, co sach, hoc sach
so sanh » do sanh
de hoc » te hoc, dien hoc
du hoc » tu hoc, duoc 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 nghien ((de hoc) or (du hoc)) ) or ( ((so sach) OR (so sanh)) kinh nghien ad hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu canh tinh nghien ((de hoc) OR (du hoc)) ) OR ( ((so sach) OR (so sanh)) kinh nghien ad hoc )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( tu canh tinh nghien ((de hoc) or (du hoc)) ) or ( ((so sach) OR (so sanh)) kinh nghien ad hoc ))".
• Adding a wildcard symbol may retrieve word variants: (( tu canh tinh nghien ((de hoc) or (du hoc)) ) or ( ((so sach) OR (so sanh)) kinh nghien ad hoc ))*.