Perhaps you should try some spelling variations:
sach thu » sach thue, sach thieu, sach tham
hieu san » hieu van, hieu sau, chieu sang
va triet » va thiet, va trien, ve triet
sach ty » sach y, sach tu, xach tay
nang xa » nang x, lang xa, nang ma
duc van » duc va, duc tan, duc manh
minh vi » minh voi, minh va, minh ve
dinh vi » dinh ve, dinh viet, dinh tri
pham » phan

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: toc ((sach ty) OR (sach thu)) nang xa hoi. hieu san pham duc van ((minh vi) OR (dinh vi)) va triet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc ((sach ty) or (sach thu)) nang xa hoi. hieu san pham duc van ((minh vi) OR (dinh vi)) va triet~".
• Adding a wildcard symbol may retrieve word variants: toc ((sach ty) or (sach thu)) nang xa hoi. hieu san pham duc van ((minh vi) OR (dinh vi)) va triet*.