Perhaps you should try some spelling variations:
tham thuc » nham thuc, pham thuc, tam thuc
tu cach » tu cac
va hanh » van hanh, va thanh, va danh
xa hanh » xa thanh, xa khanh, da hanh
ve tham » va tham, ve cham, vi tham
hieu ve » hieu va, hieu van
su sach » so sach, vu sach
cua te » cua tu
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: ((tu cach) or (su sach)) ky nang x hoi. hieu ve tham thuc ((xa hanh) or (va hanh)) dai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu cach) OR (su sach)) ky nang x hoi. hieu ve tham thuc ((xa hanh) OR (va hanh)) dai cua te.
• Adding a wildcard symbol may retrieve word variants: ((tu cach) or (su sach)) ky nang x hoi. hieu ve tham thuc ((xa hanh) or (va hanh)) dai cua te*.