Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
cac thoi » cac toi, cac hop, cac tro
va doanh » van doanh, vay doanh, va danh
te sach » toc sach
dao cao » dao tao, bao cao, do cao
ky lang » ky nang, ky dang, ky tang
lang xa » lang ha, dang xay, lang van
cac toc » cac toi, cac nuoc
tao cao » bao cao, toan cao
sach ky » sac ky, sach y, sach ty

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: te sach ky lang xa hoi. hieu van ((cac toc) OR (cac thoi)) va doanh ((dao cao) OR (tao cao)) me~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ky lang xa hoi. hieu van ((cac toc) or (cac thoi)) va doanh ((dao cao) OR (tao cao)) me~".
• Adding a wildcard symbol may retrieve word variants: te sach ky lang xa hoi. hieu van ((cac toc) or (cac thoi)) va doanh ((dao cao) OR (tao cao)) me*.