Perhaps you should try some spelling variations:
cam thuc » am thuc, cam thu, can thuc
nam thuc » nam thuoc, am thuc, nam thu
so sach » so sanh, bo sach, co sach
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
hieu ve » hieu va, hieu van
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, cua triet
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: so sach ky nang xa hoi. hieu ve ((cam thuc) or (nam thuc)) va hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ky nang xa hoi. hieu ve ((cam thuc) OR (nam thuc)) va hanh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: so sach ky nang xa hoi. hieu ve ((cam thuc) or (nam thuc)) va hanh vi cua tre*.