Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
sach dao » lanh dao
van cau » van dau, van hau, van chat
cuu tre » cau tren, cau treo
va hanh » van hanh, va thanh, va danh
cau luc » cau truc, cau phuc
sach lo » sach doi, sach hoi, sach moi
cua tre » cua te, cua triet, dua tren
hang x » nang x, hoang xa, chang xu
luc va » duc va, tuc va, loc va

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu ((sach lo) or (sach dao)) hang x ho. hieu van cau luc va hanh vi ((cuu tre) OR (cua tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach lo) OR (sach dao)) hang x ho. hieu van cau luc va hanh vi ((cuu tre) OR (cua tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach lo) or (sach dao)) hang x ho. hieu van cau luc va hanh vi ((cuu tre) OR (cua tre))".
• Adding a wildcard symbol may retrieve word variants: tu ((sach lo) or (sach dao)) hang x ho. hieu van cau luc va hanh vi ((cuu tre) OR (cua tre))*.