Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
cua triet » cua viet, su triet, va triet
dang xay » dang van, van xay
nam thuc » nam thuoc, am thuc, nam thu
toc sach » hoc sach, doc sach, nuoc sach
ky dang » ky nang, ky danh
xay hoi » xa hoi, tay hoi, cay phoi
hieu va » lieu va, hieu qua
vai cua » dai cua, hai cua, lai cua
va dan » ca dan, va dao, va dap
va dau » va dao
va nam » van nam, ha nam, va nay

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