Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
cau thuc » cau truc, cuu thuc, can thuc
sach ky » sac ky, sach y, sach ty
doi cua » dai cua, hoi cua, dong cua
va hanh » van hanh, va thanh, va danh
thuc va » thuc vat, thuc dan, thuc day
hieu ve » hieu va, hieu van
sang ma » tang ma, sang tao, mang may
nang ma » tang ma, nang cao, mang may
di cua » dai cua, de cua, do cua
ve cau » ke cau, va cau, ve cac

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: thuoc sach ky ((nang ma) or (sang ma)) hoi. hieu ve cau thuc va hanh ((di cua) OR (doi cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuoc sach ky ((nang ma) OR (sang ma)) hoi. hieu ve cau thuc va hanh ((di cua) OR (doi cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuoc sach ky ((nang ma) or (sang ma)) hoi. hieu ve cau thuc va hanh ((di cua) OR (doi cua)) tre".
• Adding a wildcard symbol may retrieve word variants: thuoc sach ky ((nang ma) or (sang ma)) hoi. hieu ve cau thuc va hanh ((di cua) OR (doi cua)) tre*.