Perhaps you should try some spelling variations:
day thanh » dao thanh, dat thanh, da thanh
cua triet » cua viet, su triet, va triet
cam thuc » nam thuc, cam thu, can thuc
ban hanh » ban hang
vu sach » vu bach, su sach, vu khach
sach ky » sac ky, sach y, sach ty
hieu va » lieu va, hieu qua
di cua » dai cua, doi cua, de cua
x hoi » xa hoi, o hoi, x ho

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

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