Perhaps you should try some spelling variations:
thuoc toan » thuoc tan, thuoc thanh, thuat toan
phau thong » phap thong, phan thong, phan thuong
khau thong » khau thuong, khap thong, khau tong
thuoc ban » thuoc tan, thuoc dang, thu ban
thu sach » tu sach, thuat sach, thuoc sach
sach cay » sach cap, sach hay, sach nay

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach cay ((thuoc toan) or (thuoc ban)) khoa ((phau thong) or (khau thong))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach cay ((thuoc toan) OR (thuoc ban)) khoa ((phau thong) OR (khau thong)).
• Adding a wildcard symbol may retrieve word variants: thu sach cay ((thuoc toan) or (thuoc ban)) khoa ((phau thong) or (khau thong))*.