Perhaps you should try some spelling variations:
sach thien » sach thieu, sach tien, cach thien
thien bang » khien bang, thien ban, thien dang
cau triet » cau trieu, su triet, cua triet
hieu van » hieu va, thien van, lieu va
va chinh » tai chinh, te chinh
dua tren » dung tren
so sach » so sanh, bo sach, co sach
bang xa » lang xa, bang va, mang xa
van cau » van dau, van hau, van chat
truc va » thuc va, thuc vat, trung va

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach thien bang xa hoi. hieu van cau truc va chinh tri ((dua tren) or (cau triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach thien bang xa hoi. hieu van cau truc va chinh tri ((dua tren) OR (cau triet)).
• Adding a wildcard symbol may retrieve word variants: so sach thien bang xa hoi. hieu van cau truc va chinh tri ((dua tren) or (cau triet))*.