Perhaps you should try some spelling variations:
tham thuc » nham thuc, pham thuc, tam thuc
va triet » va thiet, va trien, ve triet
sach thi » sach tai, sach thieu, sach tham
hanh tai » thanh tai, hang tai, han tai
sach thu » sach thue, sach thieu, sach tham
hieu va » lieu va, hieu qua
va tham » van tham, va cham, va thanh
thuc va » thuc vat, thuc dan, thuc day
va hanh » van hanh, va thanh, va danh
ca hoi » cau hoi, cua hoi, co hoi
tai va » thai va, mai va, tri va

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 thi) OR (sach thu)) hang ((ca hoi) or (xa hoi)). hieu va tham thuc va hanh tai va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach thi) OR (sach thu)) hang ((ca hoi) OR (xa hoi)). hieu va tham thuc va hanh tai va triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach thi) OR (sach thu)) hang ((ca hoi) or (xa hoi)). hieu va tham thuc va hanh tai va triet".
• Adding a wildcard symbol may retrieve word variants: tu ((sach thi) OR (sach thu)) hang ((ca hoi) or (xa hoi)). hieu va tham thuc va hanh tai va triet*.