Perhaps you should try some spelling variations:
doanh dan » doanh ban, doanh van, doanh dao
thuong va » truong va, thong va, thuong mai
thuoc va » thuc va, thuoc ma, thuoc tai
toc sach » hoc sach, doc sach, thuoc sach
hieu van » thien van, lieu va, hieu ve
hieu va » lieu va, hieu qua
sach ky » sac ky, sach y, sach ty
lang xa » lang ha, dang xay, lang van
ky lang » ky nang, ky dang, ky tang
dan cua » dan ca, ban cua, dai cua
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: toc sach ky lang xa hoi. ((hieu van) or (hieu va)) cay ((thuoc va) OR (thuong va)) doanh dan cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky lang xa hoi. ((hieu van) OR (hieu va)) cay ((thuoc va) OR (thuong va)) doanh dan cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ky lang xa hoi. ((hieu van) or (hieu va)) cay ((thuoc va) OR (thuong va)) doanh dan cua te".
• Adding a wildcard symbol may retrieve word variants: toc sach ky lang xa hoi. ((hieu van) or (hieu va)) cay ((thuoc va) OR (thuong va)) doanh dan cua te*.