Perhaps you should try some spelling variations:
doanh dan » doanh ban, doanh van, doanh dao
toc sach » hoc sach, doc sach, thuoc sach
hieu van » hieu va, thien van, lieu va
cac nuoc » cap nuoc, hoc nuoc, cua nuoc
cac thoi » cac toi, cac hop, cac tro
va doanh » van doanh, vay doanh, va danh
tang xa » trang xa, tang ma, lang xa
dan cua » dan ca, ban cua, dai cua
y tang » ky tang, 6 tang, 7 tang
cua tu » cua tuc, cua su, cua cu

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: toc sach y tang xa hoi. hieu van ((((cac nuoc) OR (dat nuoc))) OR (cac thoi)) va doanh dan cua tu~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach y tang xa hoi. hieu van ((((cac nuoc) OR (dat nuoc))) or (cac thoi)) va doanh dan cua tu~".
• Adding a wildcard symbol may retrieve word variants: toc sach y tang xa hoi. hieu van ((((cac nuoc) OR (dat nuoc))) or (cac thoi)) va doanh dan cua tu*.