Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
va trinh » van trinh, va tinh, lap trinh
trinh ve » trinh he, trinh va, trinh vi
su sach » so sach, vu sach
tang xa » trang xa, tang ma, lang xa
van cac » van hac, van cau, van bac
cac loc » cac lop, cac toc, cac hoc
cua tre » cua triet, dua tren, cua thep
cuu tre » cau tren, cau treo
y tang » ky tang, 6 tang, 7 tang
loc va » hoc va, luc va
cua te » cua tu

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

• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y tang xa hoi. hieu van cac loc va trinh ve ((((cua tre) OR (cuu tre))) OR (cua te))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach y tang xa hoi. hieu van cac loc va trinh ve ((((cua tre) OR (cuu tre))) or (cua te))~".
• Adding a wildcard symbol may retrieve word variants: su sach y tang xa hoi. hieu van cac loc va trinh ve ((((cua tre) OR (cuu tre))) or (cua te))*.