Perhaps you should try some spelling variations:
kinh nghien » kinh nghiem, trinh nghien, kinh hien
tranh nghe » trinh nghe, anh nghe, hanh nghe
nghien du » nghiep du, nghien cuu, nghiem dau
su sach » so sach, vu sach
du canh » du hanh, do canh, luc canh
nghe du » nghe duc, nghe xu, nghe di
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: (( su sach kinh nghien du hoc ) or ( du canh tranh nghe du hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( su sach kinh nghien du hoc ) OR ( du canh tranh nghe du hoc )).
• Adding a wildcard symbol may retrieve word variants: (( su sach kinh nghien du hoc ) or ( du canh tranh nghe du hoc ))*.