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

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