Perhaps you should try some spelling variations:
nham thuc » nhan thuc, nam thuc, nham thu
nang chat » nang phat, nang cham, nang cao
cham thuc » pham thuc, tham thuc, pham thuoc
chat hoc » chat hoa, chat thom, cho hoc
can cau » van cau, ban cau, cac cau
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va, hieu van
va dan » ca dan, va dao, va dau
ca cau » cua cau, cac cau, ca cac

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 ky nang chat hoc. hieu ve ((cham thuc) OR (nham thuc)) va dan ((ca cau) or (can cau)) tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang chat hoc. hieu ve ((cham thuc) OR (nham thuc)) va dan ((ca cau) OR (can cau)) tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang chat hoc. hieu ve ((cham thuc) OR (nham thuc)) va dan ((ca cau) or (can cau)) tren".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang chat hoc. hieu ve ((cham thuc) OR (nham thuc)) va dan ((ca cau) or (can cau)) tren*.