Perhaps you should try some spelling variations:
cau thuc » cau truc, cuu thuc, can thuc
hieu cac » hieu luc, hieu va, hieu van
va hanh » van hanh, va thanh, ban hanh
va danh » va dinh, va dan, dia danh
cac cau » cac mau, bac cau, ca cau
sach ky » sac ky, sach ty, sach kem
nang xa » nang x, lang xa, nang ma
cua tre » cua te, cuu tre, cua triet

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) OR (sach y)) nang xa hoi. hieu cac cau thuc ((va danh) or (va hanh)) dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu ((sach ky) OR (sach y)) nang xa hoi. hieu cac cau thuc ((va danh) OR (va hanh)) dai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu ((sach ky) OR (sach y)) nang xa hoi. hieu cac cau thuc ((va danh) or (va hanh)) dai cua tre".
• Adding a wildcard symbol may retrieve word variants: thu ((sach ky) OR (sach y)) nang xa hoi. hieu cac cau thuc ((va danh) or (va hanh)) dai cua tre*.