Perhaps you should try some spelling variations:
vat thanh » dat thanh, gat thanh, tat thanh
vu sach » vu bach, su sach, vu khach
sach ky » sac ky, sach y, sach ty
nang xa » lang xa, nang ma, mang xa
hieu le » hieu ve, hieu he, hieu ly
na thuc » nam thuc, na thuoc, va thuc
vi cua » vai cua
di cua » dai cua, doi cua, de cua
le na » le nam, le va, le ta

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

• Performing a fuzzy search may retrieve terms with similar spellings: vu sach ky ((nang xa) OR (nang x)) hoi. hieu le na thuc vat thanh ((vi cua) or (di cua)) tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach ky ((nang xa) OR (nang x)) hoi. hieu le na thuc vat thanh ((vi cua) OR (di cua)) tu.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu sach ky ((nang xa) OR (nang x)) hoi. hieu le na thuc vat thanh ((vi cua) or (di cua)) tu".
• Adding a wildcard symbol may retrieve word variants: vu sach ky ((nang xa) OR (nang x)) hoi. hieu le na thuc vat thanh ((vi cua) or (di cua)) tu*.