Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
hieu van » hieu va, thien van, lieu va
ban hanh » ban hang
cuu thuc » cuu tac
cau thuc » cau truc, can thuc, cau phuc
hanh ve » hanh vi, hanh va, hanh kem
sach ky » sac ky, sach y, sach ty
tang ma » mang may, tang van
nang ma » sang ma, nang cao, mang may
cua tre » cua te, cuu tre, cua triet
ve cua » le cua, de cua, te cua

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