Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
duc manh » suc manh, duc anh, duc minh
phan duc » pham duc, phan tu, phan dau
hieu van » hieu va, thien van, lieu va
van phan » van phong, van thanh, luan phan
nang xa » nang x, lang xa, nang ma
sach ky » sac ky, sach y, sach kem
sach ty » sach y, sach tu, sach thu
hanh di » hanh de, hang di, danh di

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

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