Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
va trinh » van trinh, lap trinh, qua trinh
su sach » vu sach
va tinh » may tinh
cac loc » cac lop, cac toc, cac hoc
van cac » van hac, van cau, van bac
tang xa » trang xa, tang ma, lang xa
ky tang » ky nang, ky dang, kho tang
so sach » so sanh, bo sach, co sach
cua tre » cua te, cuu tre, cua triet
vi cua » vai cua, di 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) OR (so sach)) ky tang xa hoi. hieu van cac loc ((va trinh) OR (va tinh)) vi cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) OR (so sach)) ky tang xa hoi. hieu van cac loc ((va trinh) or (va tinh)) vi cua tre~".
• Adding a wildcard symbol may retrieve word variants: ((su sach) OR (so sach)) ky tang xa hoi. hieu van cac loc ((va trinh) or (va tinh)) vi cua tre*.