Perhaps you should try some spelling variations:
than thong » than thuong, toan thong, tran thong
sach tham » sach nha
tham thuc » nham thuc, pham thuc, tam thuc
hanh khoa » hang khoa, anh khoa, hanh hoa
khoa than » khoa luan, hoa thai, hoa tan
khach thi » khac thi, khach trai, quach thi
bach khoa » anh khoa
thi bach » thi bich, thi hanh, thi anh
so sach » so sanh, bo sach, co sach
thi thi » thi thai, thi thin, thi thu
khoa he » hoa he, khoa hoc, khong he

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 tham thuc hanh khoa than thong ) or ( vay khach thi thi bach khoa he thong ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( so sach tham thuc hanh khoa than thong ) OR ( vay khach thi thi bach khoa he thong )).
• Adding a wildcard symbol may retrieve word variants: (( so sach tham thuc hanh khoa than thong ) or ( vay khach thi thi bach khoa he thong ))*.