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
phuc chai » phuc cham, phuc chau, phuc hoi
chai khoa » thai khoa, chi khoa, pham khoa
hang kho » hang khoa, khang kho, hang cho
kho khan » khoa kham, khoa than
cac thuc » cach thuc, cac thu, can thuc
te sach » toc sach
khoa he » hoa he, khoa hoc, khong he

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 chai khoa he 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 chai khoa he thong )).
• Adding a wildcard symbol may retrieve word variants: (( te sach trien thuc hang kho khan thong ) or ( tu cac thuc phuc chai khoa he thong ))*.