Perhaps you should try some spelling variations:
doanh van » doanh va, doanh ban, doanh nhan
thuc day » thuc dan, thuc vat
doan van » doan va, hoang van, luan van
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
ca viet » va viet, co viet, hoa viet
ve nam » va nam, le nam, te nam
he nam » ha nam, nghe nam
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ky nang x hoi. hieu ((ve nam) or (he nam)) thuc day ((doanh van) OR (doan van)) ca viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang x hoi. hieu ((ve nam) OR (he nam)) thuc day ((doanh van) OR (doan van)) ca viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang x hoi. hieu ((ve nam) or (he nam)) thuc day ((doanh van) OR (doan van)) ca viet".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang x hoi. hieu ((ve nam) or (he nam)) thuc day ((doanh van) OR (doan van)) ca viet*.