Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
lam thuc » lam thuoc, am thuc, nam thuc
thuc day » thuc dan, thuc vat
tu sach » thu sach, su sach, te sach
ky lang » ky dang, ky tang, tay lang
hieu va » lieu va, hieu qua
hanh di » hanh de, hang di, danh di
va lam » van lam, va lap

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 va lam thuc day ((hanh di) or (hanh vi)) cua triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((ky lang) OR (ky nang)) xa hoi. hieu va lam thuc day ((hanh di) OR (hanh vi)) cua triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((ky lang) OR (ky nang)) xa hoi. hieu va lam thuc day ((hanh di) or (hanh vi)) cua triet".
• Adding a wildcard symbol may retrieve word variants: tu sach ((ky lang) OR (ky nang)) xa hoi. hieu va lam thuc day ((hanh di) or (hanh vi)) cua triet*.