Perhaps you should try some spelling variations:
doanh nghien » doanh nghiep, doanh nghi, doanh ngiep
tranh nghien » trinh nghien, tron nghien, trong nghien
sach doanh » sach danh, cac doanh, san doanh
sach tranh » canh tranh
nghien d » nghiem d, nghien o, nghiem de
so sach » so sanh, bo sach, co sach
cuu hoc » cuu thuoc, cuu khoa, cuu duoc
cua hoc » cua hoi, cua thuoc, cua nuoc
vu sach » vu bach, su sach, vu khach
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 doanh nghien ((cuu hoc) OR (cua hoc)) ) or ( vu sach tranh nghien d hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( so sach doanh nghien ((cuu hoc) OR (cua hoc)) ) OR ( vu sach tranh nghien d hoc )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( so sach doanh nghien ((cuu hoc) OR (cua hoc)) ) or ( vu sach tranh nghien d hoc ))".
• Adding a wildcard symbol may retrieve word variants: (( so sach doanh nghien ((cuu hoc) OR (cua hoc)) ) or ( vu sach tranh nghien d hoc ))*.