Perhaps you should try some spelling variations:
duong sach » duong manh
dam thuc » am thuc, dan thuc, nam thuc
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va, hieu van
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cua triet, dua tren
cuu tre » cau tren, cau treo
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: duong sach ky nang x hoi. hieu ve ((dam thuc) or (cam xuc)) va hanh vi ((cua tre) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: duong sach ky nang x hoi. hieu ve ((dam thuc) OR (cam xuc)) va hanh vi ((cua tre) OR (cuu tre)).
• Adding a wildcard symbol may retrieve word variants: duong sach ky nang x hoi. hieu ve ((dam thuc) or (cam xuc)) va hanh vi ((cua tre) or (cuu tre))*.