Perhaps you should try some spelling variations:
nam thuc » nam thuoc, am thuc, nam thu
ban hanh » ban hang
va thanh » gia thanh, ban thanh, va tinh
cua viet » ca viet, hoa viet, cua vat
vu sach » vu bach, su sach, vu khach
sach ky » sac ky, sach y, sach ty
hieu he » hieu ve, hiem he, hieu le
va hanh » van hanh, va danh, dao hanh
he nam » ha nam, nghe nam
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: vu sach ky nang x hoi. hieu he nam thuc ((((va hanh) OR (ban hanh))) or (va thanh)) di cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach ky nang x hoi. hieu he nam thuc ((((va hanh) OR (ban hanh))) OR (va thanh)) di cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu sach ky nang x hoi. hieu he nam thuc ((((va hanh) OR (ban hanh))) or (va thanh)) di cua viet".
• Adding a wildcard symbol may retrieve word variants: vu sach ky nang x hoi. hieu he nam thuc ((((va hanh) OR (ban hanh))) or (va thanh)) di cua viet*.