Perhaps you should try some spelling variations:
danh vai » danh sai, danh va, doanh van
thuc tai » thuc thai, thuoc tai, thuc tap
thuc dai » thuc dan, thuc day, thu dai
sach ky » sac ky, sach y, sach ty
tu sach » thu sach, su sach, te sach
ca viet » va viet, co viet, hoa viet
he nam » ha nam, nghe nam
ve nam » va nam, le nam, te nam
vai ca » vai cac, vai cua, bai ca
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 dai) OR (thuc tai)) danh vai 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 dai) OR (thuc tai)) danh vai 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 dai) OR (thuc tai)) danh vai ca viet".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang x hoi. hieu ((ve nam) or (he nam)) ((thuc dai) OR (thuc tai)) danh vai ca viet*.