Perhaps you should try some spelling variations:
cua viet » ca viet, hoa viet, cua vat
su sach » so sach, vu sach
ky lang » ky nang, ky dang, tay lang
ky tang » ky nang, ky dang, kho tang
hieu ve » hieu va, hieu van
cac tuc » cac toc, cac tu, cac tac
va nang » van nang, da nang, kha nang
ve cac » va cac, vien cac

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ((ky lang) or (ky tang)) xa hoi. hieu ve cac tuc ((va nang) OR (cam nang)) dai cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((ky lang) OR (ky tang)) xa hoi. hieu ve cac tuc ((va nang) OR (cam nang)) dai cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((ky lang) or (ky tang)) xa hoi. hieu ve cac tuc ((va nang) OR (cam nang)) dai cua viet".
• Adding a wildcard symbol may retrieve word variants: su sach ((ky lang) or (ky tang)) xa hoi. hieu ve cac tuc ((va nang) OR (cam nang)) dai cua viet*.