Perhaps you should try some spelling variations:
cua triet » cua viet, su triet
toc sach » hoc sach, doc sach, thuoc sach
dang xay » dang van, van xay
nam thuc » nam thuoc, nam thu, nam tu
va triet » va thiet, va trien, ve triet
sach ky » sac ky, sach y, sach ty
ky dang » ky nang, ky danh
xay hoi » xa hoi, tay hoi, cay phoi
hieu va » lieu va, hieu qua
va can » va chan, va cac, va cao

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