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