Perhaps you should try some spelling variations:
tham thuc » nham thuc, pham thuc, tam thuc
thu sach » tu sach, thuat sach, thuoc sach
su triet » su viet, su tien, ve triet
va triet » va thiet, va trien, ve triet
sang ma » tang ma, sang tao, mang may
hieu va » lieu va, hieu qua
sach ky » sac ky, sach y, sach ty
thuc va » thuc vat, thuc dan, thuc day
va hanh » van hanh, va thanh, va danh
nang ma » tang ma, nang cao, mang may
va tham » van tham, va cham, va thanh

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 ((nang ma) or (sang ma)) hoa. hieu va tham thuc va hanh vi ((su triet) or (va triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky ((nang ma) OR (sang ma)) hoa. hieu va tham thuc va hanh vi ((su triet) OR (va triet)).
• Adding a wildcard symbol may retrieve word variants: thu sach ky ((nang ma) or (sang ma)) hoa. hieu va tham thuc va hanh vi ((su triet) or (va triet))*.