Perhaps you should try some spelling variations:
manh cay » manh xay, manh cam, xanh cay
sach kem » hanh kem
cay phoi » cap phoi, tay hoi, cay cho
giai duc » giao duc, gia duc, giap duc
sach de » sach dao, sach dat, sach che
hieu va » lieu va, hieu qua
va hanh » van hanh, va thanh, va danh
vi va » vi van, vai va, vu va
thiet » thieu

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

• Performing a fuzzy search may retrieve terms with similar spellings: su ((((sach de) OR (sach kem))) or (cach de)) manh cay phoi. hieu va giai duc va hanh vi va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((((sach de) OR (sach kem))) OR (cach de)) manh cay phoi. hieu va giai duc va hanh vi va thiet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((((sach de) OR (sach kem))) or (cach de)) manh cay phoi. hieu va giai duc va hanh vi va thiet".
• Adding a wildcard symbol may retrieve word variants: su ((((sach de) OR (sach kem))) or (cach de)) manh cay phoi. hieu va giai duc va hanh vi va thiet*.