Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
sach tham » sach nha
sach thu » sach thue, sach thieu, cach thuc
cac thoi » cac toi, cac hop, cac tro
kinh ve » kinh te, dinh ve, minh ve
va kinh » va tinh, qua kinh
cac loc » cac lop, cac toc, cac hoc
hieu ve » hieu va, hieu van
nang xa » nang x, lang xa, nang ma
ve cua » le cua, de cua, te cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: su ((sach thu) OR (sach tham)) nang xa hoi. hieu ve ((cac loc) or (cac thoi)) va kinh ve cua triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach thu) OR (sach tham)) nang xa hoi. hieu ve ((cac loc) OR (cac thoi)) va kinh ve cua triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach thu) OR (sach tham)) nang xa hoi. hieu ve ((cac loc) or (cac thoi)) va kinh ve cua triet".
• Adding a wildcard symbol may retrieve word variants: su ((sach thu) OR (sach tham)) nang xa hoi. hieu ve ((cac loc) or (cac thoi)) va kinh ve cua triet*.