Perhaps you should try some spelling variations:
vien sach » dien sach, viet sach, kien sach
vu sach » vu bach, su sach, vu khach
sach ky » sac ky, sach y, sach ty
nang xa » lang xa, nang ma, mang xa
va hanh » van hanh, va thanh, va danh
hanh di » hanh vi, hanh de, hang di
di cua » dai cua, doi cua, de cua
cua te » cua tu

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 ((vien sach) OR (vien bach)) nuoc va hanh di cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach ky ((nang xa) OR (nang x)) hoi. hieu ((vien sach) OR (vien bach)) nuoc va hanh di cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu sach ky ((nang xa) or (nang x)) hoi. hieu ((vien sach) OR (vien bach)) nuoc va hanh di cua te".
• Adding a wildcard symbol may retrieve word variants: vu sach ky ((nang xa) or (nang x)) hoi. hieu ((vien sach) OR (vien bach)) nuoc va hanh di cua te*.