Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
cham thuc » nham thuc, pham thuc, tham thuc
thu sach » thuat sach, thuoc sach, thu hoach
vat hanh » vat thanh, van hanh, va hanh
hanh de » hanh ve, hanh kem
ve cham » va cham, ve chat, vu cham
hieu ve » hieu va, hieu van
tu sach » su sach, te sach, tu cach
tang ma » mang may, tang van
de cua » le cua, te cua, dieu cua

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

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