Perhaps you should try some spelling variations:
tham thuc » nham thuc, pham thuc, tam thuc
thu sach » tu sach, thuat sach, thuoc sach
nang ma » tang ma, nang cao, mang may
sang ma » tang ma, sang tao, mang may
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
vai cua » dai cua, hai cua, lai cua
vi cua » di cua

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