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 thu, sach thieu, sach tham
han thai » han tai, ban thai, van thai
sach tai » sach bai, sach tham, sach dao
hieu va » lieu va, hieu qua
va tham » van tham, va cham, va thanh
thuc va » thuc vat, thuc dan, thuc day
thai va » thai van
co hoi » co hoc, co loi
va han » va phan, van han, va hanh

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