Perhaps you should try some spelling variations:
tham thuc » nham thuc, tam thuc, thai thuc
pham thuc » phap thuc, pham chuc, nham thuc
cua viet » ca viet, hoa viet, cua vat
thanh do » thanh de, thanh pho, thanh hoa
hoc sach » hoc sinh, hoc cac, hoc anh
xa thanh » va thanh, ha thanh, ta thanh
su sach » so sach, vu sach
hieu ve » hieu va, hieu van
do cua » doi cua, co 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) or (hoc sach)) ky nang x hoi. hieu ve ((tham thuc) OR (pham thuc)) xa thanh do cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (hoc sach)) ky nang x hoi. hieu ve ((tham thuc) OR (pham thuc)) xa thanh do cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) or (hoc sach)) ky nang x hoi. hieu ve ((tham thuc) OR (pham thuc)) xa thanh do cua viet".
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (hoc sach)) ky nang x hoi. hieu ve ((tham thuc) OR (pham thuc)) xa thanh do cua viet*.