Perhaps you should try some spelling variations:
dao thanh » ban thanh, tro thanh, de thanh
cam thuc » nam thuc, cam thu, can thuc
cac nhan » ca nhan, cac nha, cam nhan
vu sach » vu bach, su sach, vu khach
sach ky » sac ky, sach y, sach ty
cua tre » cua te, cuu tre, cua triet
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. lieu va ((cam thuc) OR (am thuc)) ((dao thanh) or (cac nhan)) di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach ky nang x hoi. lieu va ((cam thuc) OR (am thuc)) ((dao thanh) OR (cac nhan)) di cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu sach ky nang x hoi. lieu va ((cam thuc) OR (am thuc)) ((dao thanh) or (cac nhan)) di cua tre".
• Adding a wildcard symbol may retrieve word variants: vu sach ky nang x hoi. lieu va ((cam thuc) OR (am thuc)) ((dao thanh) or (cac nhan)) di cua tre*.