Perhaps you should try some spelling variations:
khan thong » khap thong, khau thong, nhan thong
sach tranh » canh tranh
sach tham » sach nha
tham thuc » nham thuc, pham thuc, tam thuc
thuc dung » thuoc dung, thuy dung, tuc dung
dung khoa » dung cho
pho thong » he thong
tranh thi » tranh thai, tran thi, trinh thi
khoa pho » khoa phu, khoa khoa, khoa phau
kho khan » khoa kham, khoa than
tu sach » thu sach, su sach, te sach
thi tac » thi tam, thi thao, thi tran
tac kho » toc kho, tac cho, cac khoi

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( tu sach tham thuc dung khoa pho thong ) or ( tu sach tranh thi tac kho khan thong ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu sach tham thuc dung khoa pho thong ) OR ( tu sach tranh thi tac kho khan thong )).
• Adding a wildcard symbol may retrieve word variants: (( tu sach tham thuc dung khoa pho thong ) or ( tu sach tranh thi tac kho khan thong ))*.