Perhaps you should try some spelling variations:
thanh doi » thanh loi, thanh moi, thanh do
hieu van » hieu va, thien van, lieu va
va thanh » gia thanh, ban thanh, va tinh
te sach » toc sach
cua tre » cuu tre, cua triet, dua tren
cac luc » cau luc, coc luc, cac nuoc
van cac » van hac, van cau, van bac
sach ty » sach y, sach tu, sach thu
hang do » hang doi, dang do, hang di
luc va » duc va, tuc va, loc va
hang o » hang o2, hoang o, thang o
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: te sach ty ((hang o) OR (hang do)) hoi. hieu van cac luc va thanh doi ((cua tre) or (cua te))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ty ((hang o) OR (hang do)) hoi. hieu van cac luc va thanh doi ((cua tre) OR (cua te)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ty ((hang o) OR (hang do)) hoi. hieu van cac luc va thanh doi ((cua tre) or (cua te))".
• Adding a wildcard symbol may retrieve word variants: te sach ty ((hang o) OR (hang do)) hoi. hieu van cac luc va thanh doi ((cua tre) or (cua te))*.