Perhaps you should try some spelling variations:
dat thanh » dao thanh, dat khanh, dang thanh
cam thuc » am thuc, cam thu, can thuc
nam thuc » nam thuoc, am thuc, nam thu
ban hanh » ban hang
su sach » so sach, vu sach
hieu ve » hieu va, hieu van
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
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 y nang x hoi. hieu ve ((cam thuc) OR (nam thuc)) ((dat thanh) or (ban hanh)) dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y nang x hoi. hieu ve ((cam thuc) OR (nam thuc)) ((dat thanh) OR (ban hanh)) dai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach y nang x hoi. hieu ve ((cam thuc) OR (nam thuc)) ((dat thanh) or (ban hanh)) dai cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach y nang x hoi. hieu ve ((cam thuc) OR (nam thuc)) ((dat thanh) or (ban hanh)) dai cua tre*.