Perhaps you should try some spelling variations:
cham thuc » nham thuc, pham thuc, tham thuc
thu sach » tu sach, thuat sach, thuoc sach
thuc dan » thuc hanh, hoc dan, thuc vat
ty hang » ly hang, thi hang, thu hang
cao hoi » cau hoi, co hoi, cao hoc
hieu vu » hieu va, hieu ve, hieu su
vu cham » va cham, vu kham, tu cham
dan dan » dang dan, ban dan, dao dan
dan vai » dan va, dan tai, dan vat
vai va » mai va, dai va, hai va
thiet » thieu

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach ((ty hang) OR (ty xang)) cao hoi. hieu vu cham thuc dan dan vai va thiet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ((ty hang) OR (ty xang)) cao hoi. hieu vu cham thuc dan dan vai va thiet".
• Adding a wildcard symbol may retrieve word variants: thu sach ((ty hang) OR (ty xang)) cao hoi. hieu vu cham thuc dan dan vai va thiet*.