Perhaps you should try some spelling variations:
sach tham » sach nha
cua triet » cua viet, su triet, va triet
sach thu » sach thue, sach thieu, cach thuc
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
cac duc » cac du, cao duc, cac dac
han tai » hang tai, nhan tai, van tai
cua tre » cua te, cuu tre, dua tren
va han » va phan, van han, va hanh

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

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