Perhaps you should try some spelling variations:
sach tranh » canh tranh
nghiep cuu » nghien cuu, nghiep cua, nghiep cau
cac doanh » cac dan, cac dang, van doanh
nghiem de » nghiem d, nghiem do, nghiem te
nghien d » nghiem d, nghien o, nghiem do
su sach » so sach, vu sach
so cac » sao cac, so cap, o cac

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

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