Perhaps you should try some spelling variations:
te sach » toc sach
sach ky » sac ky, sach y, sach ty
mang xa » lang xa, mang may, dang xay
tang ma » mang may, tang van
hieu va » lieu va, hieu qua
cac duc » cac du, cao duc, cac dac
va danh » va dinh, va dan, va hanh
co cua » con cua, cong cua, cuoi cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sach ky ((mang xa) or (tang ma)) hoi. hieu va cac duc va danh ((ca cua) OR (co cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky ((mang xa) OR (tang ma)) hoi. hieu va cac duc va danh ((ca cua) OR (co cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ky ((mang xa) or (tang ma)) hoi. hieu va cac duc va danh ((ca cua) OR (co cua)) tre".
• Adding a wildcard symbol may retrieve word variants: te sach ky ((mang xa) or (tang ma)) hoi. hieu va cac duc va danh ((ca cua) OR (co cua)) tre*.