Perhaps you should try some spelling variations:
sach trien » sach tien, sach tren, sach thieu
trien thuc » trien thuoc, tren thuc, trien thuat
thuc khang » thuoc khang, thuc khong, thuoc khong
khan thong » khap thong, khau thong, nhan thong
khang kho » khong kho, khong khoa, hang khoa
pho thong » he thong
kho khan » khoa kham, khoa than
cac thuc » cach thuc, cac thu, can thuc
thuc phu » thuc pham, thuc thuc, thuc thi
cac khoi » cac thoi, cac khoan, cach thoi
khoi pho » khoi tho, khoi khoa, hoc pho
te sach » toc sach
phu cac » phuc cac, pha cac, phu can

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 trien thuc khang kho khan thong ) or ( tu cac thuc phu cac khoi pho thong ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( te sach trien thuc khang kho khan thong ) OR ( tu cac thuc phu cac khoi pho thong )).
• Adding a wildcard symbol may retrieve word variants: (( te sach trien thuc khang kho khan thong ) or ( tu cac thuc phu cac khoi pho thong ))*.