Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
dan hanh » dang hanh, dan khanh, dan thanh
thuc dan » thuc hanh, hoc dan, thuc vat
nam thuc » nam thuoc, am thuc, nam thu
hieu van » hieu va, thien van, lieu va
hanh di » hanh vi, hanh de, hang di
sach ky » sach y, sach ty, sach kem
nang xa » lang xa, nang ma, mang xa
sac ky » cac ky, sai ky
di cua » dai cua, doi cua, de cua

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: su ((sach ky) OR (sac ky)) ((nang xa) OR (nang x)) hoi. hieu van nam thuc dan hanh di cua triet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach ky) or (sac ky)) ((nang xa) OR (nang x)) hoi. hieu van nam thuc dan hanh di cua triet~".
• Adding a wildcard symbol may retrieve word variants: su ((sach ky) or (sac ky)) ((nang xa) OR (nang x)) hoi. hieu van nam thuc dan hanh di cua triet*.