Perhaps you should try some spelling variations:
cham thuc » nham thuc, pham thuc, tham thuc
van hanh » van thanh, ban hanh, van anh
te sach » toc sach
sach ty » sach y, sach tu, sach thu
va hanh » va thanh, va danh, ban hanh
va cham » va chat, va tham
hieu va » lieu va, hieu qua
lang xa » lang ha, dang xay, lang van
nang xa » nang x, nang ma, mang xa
cuu tre » cua tre, cau tren, cau treo
di cuu » di cau, di cua, dinh cuu

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

• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ty ((nang xa) OR (lang xa)) hoi. hieu va cham thuc ((va hanh) OR (van hanh)) di cuu tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ty ((nang xa) or (lang xa)) hoi. hieu va cham thuc ((va hanh) OR (van hanh)) di cuu tre~".
• Adding a wildcard symbol may retrieve word variants: te sach ty ((nang xa) or (lang xa)) hoi. hieu va cham thuc ((va hanh) OR (van hanh)) di cuu tre*.