Perhaps you should try some spelling variations:
doc sach » hoc sach, toc sach, nuoc sach
sach thu » sach thue, sach thieu, sach tham
hai cua » thai cua, dai cua, hoi cua
lai cua » dai cua, lai chau, thai cua
va hanh » van hanh, va thanh, va danh
hieu va » lieu va, hieu qua
nang xa » lang xa, nang ma, mang xa
cac tuc » cac toc, cac tu, cac tac
tuc va » thuc va, truc va, tuc xa

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

• Performing a fuzzy search may retrieve terms with similar spellings: doc sach thu ((nang xa) OR (nang x)) hoi. hieu va cac tuc va hanh ((lai cua) or (hai cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc sach thu ((nang xa) OR (nang x)) hoi. hieu va cac tuc va hanh ((lai cua) OR (hai cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc sach thu ((nang xa) OR (nang x)) hoi. hieu va cac tuc va hanh ((lai cua) or (hai cua)) tre".
• Adding a wildcard symbol may retrieve word variants: doc sach thu ((nang xa) OR (nang x)) hoi. hieu va cac tuc va hanh ((lai cua) or (hai cua)) tre*.