Perhaps you should try some spelling variations:
tran thanh » ban thanh, van thanh, quan thanh
tan thanh » tang thanh, toan thanh, ban thanh
vu sach » vu bach, su sach, vu khach
sach ty » sach y, sach tu, sach thu
xang xa » lang xa, mang xa, ang xa
qua cac » cua cac
cac duc » cac du, cao duc, cac dac
cua tre » cuu tre, cua triet, dua tren
cua te » cua tu

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

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