Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
ban hanh » ban hang
quoc ban » quoc bao, quoc lan, quoc quan
cac quoc » cac nuoc, cac cuoc, cao quoc
nang ma » tang ma, sang ma, nang cao
sach ky » sac ky, sach y, sach kem
lang xa » lang ha, dang xay, lang van
hieu va » lieu va, hieu qua
sach ty » sach y, sach tu, sach thu
vi cua » vai cua, di cua

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: doc ((sach ky) OR (sach ty)) ((nang ma) or (lang xa)) hoi. hieu va cac quoc ban hanh vi cua triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc ((sach ky) OR (sach ty)) ((nang ma) OR (lang xa)) hoi. hieu va cac quoc ban hanh vi cua triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc ((sach ky) OR (sach ty)) ((nang ma) or (lang xa)) hoi. hieu va cac quoc ban hanh vi cua triet".
• Adding a wildcard symbol may retrieve word variants: doc ((sach ky) OR (sach ty)) ((nang ma) or (lang xa)) hoi. hieu va cac quoc ban hanh vi cua triet*.