Perhaps you should try some spelling variations:
pham thuc » phap thuc, pham chuc, nham thuc
hoc viet » hoc hien
vat hanh » vat thanh, van hanh, va hanh
hieu van » hieu va, thien van, lieu va
tang van » dang van, hoang van, trong van
su sach » vu sach
van hoc » van hoa
ky tang » ky nang, ky dang, kho tang
so sach » so sanh, bo sach, co sach
hieu ve » hieu va
vi hoc » li hoc, va hoc

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 van hoc. ((hieu ve) OR (hieu van)) pham thuc vat hanh vi hoc viet~.
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (so sach)) ky tang van hoc. ((hieu ve) or (hieu van)) pham thuc vat hanh vi hoc viet*.