Perhaps you should try some spelling variations:
doanh nghien » doanh nghiep, doanh nghi, doanh ngiep
sach tranh » canh tranh
cac doanh » cac dan, cac dang, van doanh
nghiem de » nghiem do, nghiem te, nghiem ve
nghiem d » nghiem do, nghiem _, nghiem h
sao cac » sat cac, tao cac
su sach » so sach, vu sach

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( sao cac doanh nghien cuu khoa ) or ( su sach tranh ((nghiem d) or (nghiem de)) hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( sao cac doanh nghien cuu khoa ) OR ( su sach tranh ((nghiem d) OR (nghiem de)) hoc )).
• Adding a wildcard symbol may retrieve word variants: (( sao cac doanh nghien cuu khoa ) or ( su sach tranh ((nghiem d) or (nghiem de)) hoc ))*.