Perhaps you should try some spelling variations:
va triet » va thiet, va trien, ve triet
van nang » van quang, van ban, van dong
hieu van » hieu va, thien van, lieu va
sach thu » sach thue, sach thieu, sach tham
xang xa » lang xa, mang xa, ang xa
sach ty » sach y, sach tu, xach tay
va hanh » van hanh, va thanh, va danh
cuu tre » cua tre, cau tren, cau treo
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: su ((sach ty) OR (sach thu)) xang xa hoi. hieu van nang luc va hanh vi ((cuu tre) or (va triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach ty) OR (sach thu)) xang xa hoi. hieu van nang luc va hanh vi ((cuu tre) OR (va triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach ty) OR (sach thu)) xang xa hoi. hieu van nang luc va hanh vi ((cuu tre) or (va triet))".
• Adding a wildcard symbol may retrieve word variants: su ((sach ty) OR (sach thu)) xang xa hoi. hieu van nang luc va hanh vi ((cuu tre) or (va triet))*.