Perhaps you should try some spelling variations:
ngay luc » nhan luc, nay lua, ngay sua
ngay doc » ngay do, ngay moi, ngay de
so sach » so sanh, bo sach, co sach
sach ty » sach y, sach tu, sach thu
xang xa » lang xa, mang xa, ang xa
cua tre » cua te, cuu tre, cua triet
ca dan » cac dan, ca dao
dan vi » doan vi, don vi, dan va
vi cua » vai cua, di cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach ty xang xa hoi. lieu va ((((ngay luc) OR (ngay doc))) or (ngap lut)) ca dan vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ty xang xa hoi. lieu va ((((ngay luc) OR (ngay doc))) OR (ngap lut)) ca dan vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ty xang xa hoi. lieu va ((((ngay luc) OR (ngay doc))) or (ngap lut)) ca dan vi cua tre".
• Adding a wildcard symbol may retrieve word variants: so sach ty xang xa hoi. lieu va ((((ngay luc) OR (ngay doc))) or (ngap lut)) ca dan vi cua tre*.