Perhaps you should try some spelling variations:
sach thanh » sach tranh, sach tham, danh thanh
thanh khoe » thanh pho, thanh hoa, than khoi
khoe sach » khoa sach, hoc sach, khoe sinh
khoa than » khoa luan, hoa thai, hoa tan
toc sach » hoc sach, doc sach, thuoc sach
khoa phu » khoa phau, khoa thu, hoa phu

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach thanh khoe sach ((khoa than) or (khoa phu)) thong~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach thanh khoe sach ((khoa than) OR (khoa phu)) thong.
• Adding a wildcard symbol may retrieve word variants: toc sach thanh khoe sach ((khoa than) or (khoa phu)) thong*.