Perhaps you should try some spelling variations:
cham thuc » nham thuc, pham thuc, tham thuc
cua viet » ca viet, hoa viet, cua vat
sach tu » sach thu, cach tu, sach uu
cao hoi » cau hoi, co hoi, cao hoc
sach ty » sach y, sach thu, xach tay
ve cham » va cham, ve chat, vu cham
thuc va » thuc vat, thuc dan, thuc day
dinh vi » dinh ve, dinh viet, dinh tri
hieu ve » hieu va, hieu van

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) OR (sach tu)) nang cao hoi. hieu ve 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) OR (sach tu)) nang cao hoi. hieu ve 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) OR (sach tu)) nang cao hoi. hieu ve cham thuc va ((dinh vi) or (chinh tri)) cua viet".
• Adding a wildcard symbol may retrieve word variants: toc ((sach ty) OR (sach tu)) nang cao hoi. hieu ve cham thuc va ((dinh vi) or (chinh tri)) cua viet*.