Perhaps you should try some spelling variations:
cham thuc » nham thuc, pham thuc, tham thuc
cua triet » cua viet, su triet, va triet
sach nay » sach hay, sach vay, sach nang
co sach » bo sach, cuon sach, hoc sach
danh vi » hanh vi, dinh vi, danh di
va danh » va dinh, va dan, va hanh
thuc va » thuc vat, thuc dan, thuc day
hieu ve » hieu va, hieu van
ve cham » va cham, ve chat, vu cham
tang ma » tang van

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

• Performing a fuzzy search may retrieve terms with similar spellings: co sach nay ((tang ma) OR (mang may)) hoi. hieu ve cham thuc va danh vi ((cua triet) or (cua vat))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: co sach nay ((tang ma) OR (mang may)) hoi. hieu ve cham thuc va danh vi ((cua triet) OR (cua vat)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "co sach nay ((tang ma) OR (mang may)) hoi. hieu ve cham thuc va danh vi ((cua triet) or (cua vat))".
• Adding a wildcard symbol may retrieve word variants: co sach nay ((tang ma) OR (mang may)) hoi. hieu ve cham thuc va danh vi ((cua triet) or (cua vat))*.