Perhaps you should try some spelling variations:
cham thuc » nham thuc, pham thuc, tham thuc
thuc day » thuc dan, thuc vat
cua viet » ca viet, hoa viet, cua vat
nang ma » tang ma, sang ma, nang cao
sach ty » sach tu, sach thu, xach tay
ve cham » va cham, ve chat, vu cham
dinh vi » dinh ve, dinh viet, dinh tri
hieu ve » hieu va, hieu van
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) OR (sach y)) nang ma hoi. hieu ve cham thuc day ((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 y)) nang ma hoi. hieu ve cham thuc day ((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 y)) nang ma hoi. hieu ve cham thuc day ((dinh vi) or (chinh tri)) cua viet".
• Adding a wildcard symbol may retrieve word variants: toc ((sach ty) OR (sach y)) nang ma hoi. hieu ve cham thuc day ((dinh vi) or (chinh tri)) cua viet*.