Perhaps you should try some spelling variations:
nguoi sach » nguoi san, nuoc sach
cau thuc » cau truc, cuu thuc, can thuc
thuc van » thuc vat, thuc dan, thuc va
van hanh » van thanh, ban hanh, van anh
sach ky » sac ky, sach y, sach ty
nang ma » tang ma, sang ma, nang cao
hieu ve » hieu va, hieu van
hanh di » hanh vi, hanh de, hang di
cua tre » cua te, cuu tre, cua triet
ve cau » ke cau, va cau, ve cac
di cua » dai cua, doi cua, de cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: nguoi sach ky ((nang ma) or (nang x)) hoi. hieu ve cau thuc van hanh di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: nguoi sach ky ((nang ma) OR (nang x)) hoi. hieu ve cau thuc van hanh di cua tre.
• Adding a wildcard symbol may retrieve word variants: nguoi sach ky ((nang ma) or (nang x)) hoi. hieu ve cau thuc van hanh di cua tre*.