Perhaps you should try some spelling variations:
van trinh » van thinh, van tinh, dan trinh
hieu van » hieu va, thien van, lieu va
va trinh » va tinh, lap trinh, qua trinh
su sach » so sach, vu sach
cac hoc » cach hoc, cac hop, bac hoc
cua tre » cua te, cuu tre, cua triet
sach ky » sac ky, sach y, sach ty
cac loc » cac lop, cac toc, cac nuoc
tang xa » trang xa, tang ma, lang xa
ky tang » ky nang, ky dang, kho tang
ve cua » le cua, de cua, te cua

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 ky tang xa hoi. hieu van ((cac loc) OR (cac hoc)) ((va trinh) OR (van trinh)) ve cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky tang xa hoi. hieu van ((cac loc) or (cac hoc)) ((va trinh) OR (van trinh)) ve cua tre~".
• Adding a wildcard symbol may retrieve word variants: su sach ky tang xa hoi. hieu van ((cac loc) or (cac hoc)) ((va trinh) OR (van trinh)) ve cua tre*.