Perhaps you should try some spelling variations:
sach ngoc » sach ngon, sach nuoc, bich ngoc
sach ngan » sach ngon, sach nha, sach han
toc sach » hoc sach, doc sach, thuoc sach
thu sach » tu sach, thuat sach, thuoc sach
hai khi » phai khi, thai khi, hai thi
my khi » ly khi, ky khi, my chi
y khi » ly khi, ky khi, y chi

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( toc sach ngan ((y khi) OR (my khi)) đong luc ) or ( thu sach ngoc hai khi đong luc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( toc sach ngan ((y khi) OR (my khi)) đong luc ) OR ( thu sach ngoc hai khi đong luc )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( toc sach ngan ((y khi) OR (my khi)) đong luc ) or ( thu sach ngoc hai khi đong luc ))".
• Adding a wildcard symbol may retrieve word variants: (( toc sach ngan ((y khi) OR (my khi)) đong luc ) or ( thu sach ngoc hai khi đong luc ))*.