Perhaps you should try some spelling variations:
te sach » toc sach
sach ty » sach y, sach tu, sach thu
cua tre » cua te, cua triet, dua tren
tinh di » tinh doi, trinh di, tinh da
va tinh » may tinh
cao duc » dao duc, cao suc, giao duc
cuu tre » cau tren, cau treo
cac duc » cac du, cac dac, cac nuoc
hieu va » lieu va, hieu qua
xang x » nang x
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sach ty xang x hoi. hieu va ((cac duc) or (cao duc)) va tinh di ((cua tre) OR (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ty xang x hoi. hieu va ((cac duc) OR (cao duc)) va tinh di ((cua tre) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ty xang x hoi. hieu va ((cac duc) or (cao duc)) va tinh di ((cua tre) OR (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: te sach ty xang x hoi. hieu va ((cac duc) or (cao duc)) va tinh di ((cua tre) OR (cuu tre))*.