Perhaps you should try some spelling variations:
khan thong » khap thong, khau thong, nhan thong
thuc khang » thuoc khang, thuc khong, thuoc khong
sach tren » sach tien, sach tranh
tren thuc » trien thuc, tron thuc, trinh thuc
khang kho » khong kho, khong khoa, hang khoa
pho thong » he thong
kho khan » khoa kham, khoa than
tren phu » tren phan, bien phu, tren thi
can khoi » cac khoi, van khoi, dang khoi
khoi pho » khoi tho, khoi khoa, hoc pho
te sach » toc sach
tu sach » thu sach, su sach, tu cach
phu can » phu san, pho can, phu chuan

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( te sach tren thuc khang kho khan thong ) or ( tu sach tren phu can khoi pho thong ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( te sach tren thuc khang kho khan thong ) OR ( tu sach tren phu can khoi pho thong )).
• Adding a wildcard symbol may retrieve word variants: (( te sach tren thuc khang kho khan thong ) or ( tu sach tren phu can khoi pho thong ))*.