Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
nam thuc » nam thuoc, am thuc, nam thu
toc sach » hoc sach, doc sach, thuoc sach
dang xay » dang van, van xay
xay hoi » xa hoi, tay hoi, cay phoi
hieu va » lieu va
sach ky » sac ky, sach y, sach ty
ky dang » ky nang, ky danh
dat cua » dai cua, day cua, mat cua
va dan » ca dan, va dao, va dap
va dau » va dao

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 dang xay hoi. ((hieu va) or (hieu qua)) nam thuc ((va dan) OR (va dau)) dat cua triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky dang xay hoi. ((hieu va) OR (hieu qua)) nam thuc ((va dan) OR (va dau)) dat cua triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ky dang xay hoi. ((hieu va) or (hieu qua)) nam thuc ((va dan) OR (va dau)) dat cua triet".
• Adding a wildcard symbol may retrieve word variants: toc sach ky dang xay hoi. ((hieu va) or (hieu qua)) nam thuc ((va dan) OR (va dau)) dat cua triet*.