Perhaps you should try some spelling variations:
nguoi sach » nguoi san, nuoc sach
cua triet » cua viet, su triet, va triet
cau phuc » cau truc, chau phu, huu phuc
phuc van » thuc van, phuc va, chuc van
nang xa » lang xa, nang ma, mang xa
hieu ke » hieu kem, chieu ke, hieu ky
sach ky » sac ky, sach y, sach ty
hanh di » hanh de, hang di, danh di
ke cau » ket cau

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

• Performing a fuzzy search may retrieve terms with similar spellings: nguoi sach ky ((nang xa) or (nang x)) hoi. hieu ke cau phuc van ((hanh di) OR (hanh vi)) cua triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: nguoi sach ky ((nang xa) OR (nang x)) hoi. hieu ke cau phuc van ((hanh di) OR (hanh vi)) cua triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "nguoi sach ky ((nang xa) or (nang x)) hoi. hieu ke cau phuc van ((hanh di) OR (hanh vi)) cua triet".
• Adding a wildcard symbol may retrieve word variants: nguoi sach ky ((nang xa) or (nang x)) hoi. hieu ke cau phuc van ((hanh di) OR (hanh vi)) cua triet*.