Perhaps you should try some spelling variations:
cam thuc » am thuc, nam thuc, cam thu
vat hanh » vat thanh, van hanh, nhat hanh
ban hanh » ban hang
su sach » so sach, vu sach
hieu va » lieu va, hieu qua
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
va cam » va cham, va cac, va cao
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: su sach y nang x hoi. hieu va cam thuc ((((vat hanh) or (ban hanh))) or (va hanh)) di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y nang x hoi. hieu va cam thuc ((((vat hanh) OR (ban hanh))) OR (va hanh)) di cua tre.
• Adding a wildcard symbol may retrieve word variants: su sach y nang x hoi. hieu va cam thuc ((((vat hanh) or (ban hanh))) or (va hanh)) di cua tre*.