Perhaps you should try some spelling variations:
hieu hieu » hien hieu, hieu hien, thien hieu
hieu luc » hieu luat, hieu qua
luc nuoc » lua nuoc, luan nuoc, duoc nuoc
lai cua » dai cua, hai cua, lai chau
vai cua » dai cua, hai cua, bai cua
va danh » va dinh, va dan, va hanh
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
nang xa » lang xa, nang ma, mang xa

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

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