Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
cham thuc » nham thuc, pham thuc, tham thuc
cua triet » cua viet, su triet, va triet
tu sach » thu sach, su sach, te sach
ky lang » ky dang, ky tang, tay lang
hieu ve » hieu va, hieu van
ve cham » va cham, ve chat, vu cham
thuc va » thuc vat, thuc dan, thuc day
va hanh » van hanh, va thanh, va danh
vi cua » vai cua, di 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 (thuoc sach)) ((ky lang) OR (ky nang)) xa hoi. hieu ve cham thuc va hanh vi cua triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thuoc sach)) ((ky lang) OR (ky nang)) xa hoi. hieu ve cham thuc va hanh vi cua triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (thuoc sach)) ((ky lang) OR (ky nang)) xa hoi. hieu ve cham thuc va hanh vi cua triet".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thuoc sach)) ((ky lang) OR (ky nang)) xa hoi. hieu ve cham thuc va hanh vi cua triet*.