Perhaps you should try some spelling variations:
tham thuc » nham thuc, pham thuc, tam thuc
cua triet » su triet, va triet
hanh vai » hanh vi, hanh va, hanh tai
van hanh » van thanh, ban hanh, van anh
thuc van » thuc vat, thuc dan, thuc va
cua viet » ca viet, hoa viet, cua vat
hieu va » lieu va, hieu qua
sach ky » sach y, sach ty, sach kem
nang ma » tang ma, sang ma, nang cao
va tham » van tham, va cham, va thanh
sac ky » cac ky, sai ky

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 ky) or (sac ky)) nang ma hoa. hieu va tham thuc van hanh vai ((cua triet) OR (cua viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu ((sach ky) OR (sac ky)) nang ma hoa. hieu va tham thuc van hanh vai ((cua triet) OR (cua viet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu ((sach ky) or (sac ky)) nang ma hoa. hieu va tham thuc van hanh vai ((cua triet) OR (cua viet))".
• Adding a wildcard symbol may retrieve word variants: thu ((sach ky) or (sac ky)) nang ma hoa. hieu va tham thuc van hanh vai ((cua triet) OR (cua viet))*.