Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
dang xay » dang van, van xay
hieu van » hieu va, thien van, lieu va
te sach » toc sach
sach ky » sac ky, sach y, sach ty
van cac » van hac, van cau, van bac
cac loc » cac lop, cac toc, cac hoc
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, dua tren
loc va » hoc va, luc va

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 ((nang x) OR (dang xay)) hoi. hieu van cac loc va hanh vi ((cua tre) OR (cua triet))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ky ((nang x) or (dang xay)) hoi. hieu van cac loc va hanh vi ((cua tre) OR (cua triet))~".
• Adding a wildcard symbol may retrieve word variants: te sach ky ((nang x) or (dang xay)) hoi. hieu van cac loc va hanh vi ((cua tre) OR (cua triet))*.