Perhaps you should try some spelling variations:
cam thuc » nam thuc, cam thu, can thuc
vat hanh » vat thanh, van hanh, va hanh
cau treo » cau tren, cau triet, cau trieu
cau theo » cau thi, cau tao
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
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: su sach ky nang x hoi. hieu qua ((cam thuc) or (am thuc)) vat hanh vi ((cau treo) OR (cau theo))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang x hoi. hieu qua ((cam thuc) OR (am thuc)) vat hanh vi ((cau treo) OR (cau theo)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky nang x hoi. hieu qua ((cam thuc) or (am thuc)) vat hanh vi ((cau treo) OR (cau theo))".
• Adding a wildcard symbol may retrieve word variants: su sach ky nang x hoi. hieu qua ((cam thuc) or (am thuc)) vat hanh vi ((cau treo) OR (cau theo))*.