Perhaps you should try some spelling variations:
tham thuc » nham thuc, pham thuc, tam thuc
hanh dai » hanh tai, hanh dao, vanh dai
sach ky » sac ky, sach kem, sach hay
sach ty » sach tu, sach thu, xach tay
cao hoi » cau hoi, co hoi, cao hoc
hieu va » lieu va, hieu qua
va tham » van tham, va cham, va thanh
thuc va » thuc vat, thuc dan, thuc day
va hanh » van hanh, va thanh, va danh
dai va » mai 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: tu ((((sach ky) or (sach ty))) or (sach y)) nang cao hoi. hieu va tham thuc va hanh dai va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((((sach ky) OR (sach ty))) OR (sach y)) nang cao hoi. hieu va tham thuc va hanh dai va thiet.
• Adding a wildcard symbol may retrieve word variants: tu ((((sach ky) or (sach ty))) or (sach y)) nang cao hoi. hieu va tham thuc va hanh dai va thiet*.