Perhaps you should try some spelling variations:
tranh nghien » trinh nghien, tron nghien, trong nghien
sach tranh » canh tranh
nghiep tu » nghiep vu, nghiep vua, nghiep cua
nghien d » nghiem d, nghien o, nghiem de
so sach » so sanh, bo sach, hoc sach
co sach » bo sach, cuon sach, hoc sach
vu sach » vu bach, su sach, vu khach
tu hoc » te hoc
d hoc » du hoc, ad hoc, de hoc

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( ((so sach) OR (co sach)) doanh nghiep tu hoc ) or ( vu sach tranh nghien d hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( ((so sach) OR (co sach)) doanh nghiep tu hoc ) OR ( vu sach tranh nghien d hoc )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( ((so sach) OR (co sach)) doanh nghiep tu hoc ) or ( vu sach tranh nghien d hoc ))".
• Adding a wildcard symbol may retrieve word variants: (( ((so sach) OR (co sach)) doanh nghiep tu hoc ) or ( vu sach tranh nghien d hoc ))*.