Perhaps you should try some spelling variations:
trong hieu » trong dieu, trong hiep, trung hieu
hieu thuc » hieu thuoc, hien thuc, hieu tuc
thuc giai » thuoc giao, hoc giai, thuc thai
thue dat » thue da, thue luat, thue xuat
sach tai » sach bai, sach tham, sach dao
so sach » so sanh, bo sach, co sach
tue dai » tre dai, truc dai

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach tai ((tue dai) or (thue dat)) trong hieu thuc giai~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach tai ((tue dai) OR (thue dat)) trong hieu thuc giai.
• Adding a wildcard symbol may retrieve word variants: so sach tai ((tue dai) or (thue dat)) trong hieu thuc giai*.