Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
cach hoc » cach thuc, cach thoi, dich hoc
trinh he » trinh han, trinh hoa, trinh thi
hieu van » hieu va, thien van, lieu va
va trinh » van trinh, va tinh, lap trinh
cua tre » cua te, cuu tre, dua tren
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
cac loc » cac lop, cac toc, cac hoc
tang xa » trang xa, tang ma, lang xa
ky tang » ky nang, ky dang, kho tang

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