Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
trinh ve » trinh he, trinh va, trinh vi
va trinh » van trinh, va tinh, lap trinh
cach hoc » cach thuc, cach thoi, dich hoc
kho tang » cao tang
cua tre » cua te, cuu tre, cua triet
cac loc » cac lop, cac toc, cac hoc
ky tang » ky nang, ky dang, ky trong
ve cua » le cua, de cua, te cua
su sac » su sach, su cac, su xac

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