Perhaps you should try some spelling variations:
dang xay » dang van, van xay
nhat luc » nhan luc, nhat nuoc, nhat cua
hieu luc » hieu luat, hieu qua
tinh di » tinh doi, trinh di, tinh da
va tinh » may tinh
su sach » so sach, vu sach
lang xa » lang ha, lang van
te sach » toc sach
cua tre » cua te, cuu tre, cua triet
luc va » duc va, tuc va, loc va
di cua » dai cua, doi cua, de cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((su sach) or (te sach)) ky ((lang xa) OR (dang xay)) hoi. hieu luc nhat luc va tinh di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (te sach)) ky ((lang xa) OR (dang xay)) hoi. hieu luc nhat luc va tinh di cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) or (te sach)) ky ((lang xa) OR (dang xay)) hoi. hieu luc nhat luc va tinh di cua tre".
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (te sach)) ky ((lang xa) OR (dang xay)) hoi. hieu luc nhat luc va tinh di cua tre*.