Perhaps you should try some spelling variations:
sach tay » xach tay, sach hay, sach nay
nam thuc » nam thuoc, nam thu, nam tu
so sach » so sanh, bo sach, co sach
danh de » hanh de, dan de, dang de
va danh » va dinh, va dan, va hanh
hieu ve » hieu va, hieu van
long ha » dong ha, cong ha, dong hoa
de cua » le cua, te cua, dieu cua
cua te » cua tu

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 tay ((lang ha) OR (long ha)) hoi. hieu ve ((nam thuc) or (am thuc)) va danh de cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach tay ((lang ha) OR (long ha)) hoi. hieu ve ((nam thuc) OR (am thuc)) va danh de cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach tay ((lang ha) OR (long ha)) hoi. hieu ve ((nam thuc) or (am thuc)) va danh de cua te".
• Adding a wildcard symbol may retrieve word variants: so sach tay ((lang ha) OR (long ha)) hoi. hieu ve ((nam thuc) or (am thuc)) va danh de cua te*.