Perhaps you should try some spelling variations:
thanh tai » thanh hai, thanh toan, doanh tai
doc sach » hoc sach, toc sach, nuoc sach
hieu van » hieu va, thien van, lieu va
tai cua » thai cua, tai cuc, tri cua
thuc va » thuc vat, thuc dan, thuc day
dong ha » dong hoa, dong va, dong hoc
dang xa » dang xay, lang xa, dang ha
tuc va » truc va, tuc xa, duc va
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: doc sach y ((dang xa) or (dong ha)) hoi. hieu van nam ((tuc va) OR (thuc va)) thanh tai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc sach y ((dang xa) OR (dong ha)) hoi. hieu van nam ((tuc va) OR (thuc va)) thanh tai cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc sach y ((dang xa) or (dong ha)) hoi. hieu van nam ((tuc va) OR (thuc va)) thanh tai cua te".
• Adding a wildcard symbol may retrieve word variants: doc sach y ((dang xa) or (dong ha)) hoi. hieu van nam ((tuc va) OR (thuc va)) thanh tai cua te*.