Perhaps you should try some spelling variations:
trinh nghien » kinh nghiem, trinh thiet, trinh dien
tranh nghien » tron nghien, trong nghien, truong nghien
sach tranh » canh tranh
trinh nghe » trinh he, trinh nha
nghien du » nghiep du, nghien cuu, nghiem dau
su sach » so sach, vu sach
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 tranh nghien du hoc ) or ( duy khanh ((trinh nghe) OR (trinh nghien)) du hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( su sach tranh nghien du hoc ) OR ( duy khanh ((trinh nghe) OR (trinh nghien)) du hoc ))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( su sach tranh nghien du hoc ) or ( duy khanh ((trinh nghe) OR (trinh nghien)) du hoc ))*".