Perhaps you should try some spelling variations:
tan thanh » tran thanh, tang thanh, toan thanh
sach doi » sach hoi, sach moi, sach dao
tu sach » thu sach, su sach, te sach
nang xa » lang xa, nang ma, mang xa
hieu va » lieu va, hieu qua
cac duc » cac du, cao duc, cac dac
hoi cua » hoi chuc

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 doi ((nang xa) OR (nang x)) hoi. hieu va cac duc tan thanh ((dai cua) or (hoi cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach doi ((nang xa) OR (nang x)) hoi. hieu va cac duc tan thanh ((dai cua) OR (hoi cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach doi ((nang xa) OR (nang x)) hoi. hieu va cac duc tan thanh ((dai cua) or (hoi cua)) tre".
• Adding a wildcard symbol may retrieve word variants: tu sach doi ((nang xa) OR (nang x)) hoi. hieu va cac duc tan thanh ((dai cua) or (hoi cua)) tre*.