Perhaps you should try some spelling variations:
nang doi » nang doc, hang doi, nang dong
nang noi » nang doc
va triet » va thiet, va trien, ve triet
tu sach » thu sach, su sach, te sach
ky lang » ky dang, ky tang, tay lang
hieu ve » hieu va, hieu van
cac tuc » cac toc, cac tu, cac tac
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: tu sach ((ky lang) OR (ky nang)) xa hoi. hieu ve cac tuc xa ((nang doi) or (nang noi)) va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((ky lang) OR (ky nang)) xa hoi. hieu ve cac tuc xa ((nang doi) OR (nang noi)) va triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((ky lang) OR (ky nang)) xa hoi. hieu ve cac tuc xa ((nang doi) or (nang noi)) va triet".
• Adding a wildcard symbol may retrieve word variants: tu sach ((ky lang) OR (ky nang)) xa hoi. hieu ve cac tuc xa ((nang doi) or (nang noi)) va triet*.