Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
tat thanh » tai thanh, ta thanh, tat thang
vat thanh » dat thanh, gat thanh, viet thanh
cac thuc » cach thuc, cac thu, can thuc
co sach » bo sach, cuon sach, hoc sach
sach ky » sac ky, sach y, sach ty
nang ma » tang ma, sang ma, nang cao
nang xa » nang x, lang xa, mang xa
hieu va » lieu va, hieu qua
vi cua » vai cua, di cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: co sach ky ((nang xa) or (nang ma)) hoi. hieu va cac thuc ((vat thanh) OR (tat thanh)) vi cua triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: co sach ky ((nang xa) OR (nang ma)) hoi. hieu va cac thuc ((vat thanh) OR (tat thanh)) vi cua triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "co sach ky ((nang xa) or (nang ma)) hoi. hieu va cac thuc ((vat thanh) OR (tat thanh)) vi cua triet".
• Adding a wildcard symbol may retrieve word variants: co sach ky ((nang xa) or (nang ma)) hoi. hieu va cac thuc ((vat thanh) OR (tat thanh)) vi cua triet*.