Perhaps you should try some spelling variations:
cham thuc » nham thuc, pham thuc, tham thuc
toc sach » hoc sach, doc sach, thuoc sach
cua viet » ca viet, hoa viet, cua vat
ty hang » ly hang, ty xang, thi hang
vu cham » va cham, vu kham, tu cham
ty nang » ky nang, ty xang, ly nang
thuc va » thuc vat, thuc dan, thuc day
dinh vi » dinh ve, dinh viet, dinh tri
hieu vu » hieu va, hieu ve, hieu su
ma hoi » mai hoi, xa hoi, ma hoa

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach ((ty nang) OR (ty hang)) ma hoi. hieu vu cham thuc va ((dinh vi) or (chinh tri)) cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ((ty nang) OR (ty hang)) ma hoi. hieu vu cham thuc va ((dinh vi) OR (chinh tri)) cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ((ty nang) OR (ty hang)) ma hoi. hieu vu cham thuc va ((dinh vi) or (chinh tri)) cua viet".
• Adding a wildcard symbol may retrieve word variants: toc sach ((ty nang) OR (ty hang)) ma hoi. hieu vu cham thuc va ((dinh vi) or (chinh tri)) cua viet*.