Perhaps you should try some spelling variations:
sach doanh » sach danh, sach tranh, cac doanh
san nghiep » van nghiep, nang nghiep, luan nghiep
toc khach » soc khach, toc sach, tri khach
khach san » khach hang, thanh san
nghiep va » nghiep vu
duoc hoc » quoc hoi
tu sach » thu sach, su sach, te sach
du hoc » tu hoc
va hoc » van hoc

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

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