Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
nam thuc » nam thuoc, am thuc, nam thu
su sach » so sach, vu sach
ty lang » tay lang, ty hang, tu lang
nam duc » nam duoc, pham duc, nam buoc
va tich » va tinh, va dich
ca viet » va viet, co viet, hoa viet
va ca » va cac, va cao, va cai

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 ((ty lang) OR (ty xang)) xa hoi. hieu van ((nam duc) OR (nam thuc)) va tich va ca viet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((ty lang) OR (ty xang)) xa hoi. hieu van ((nam duc) or (nam thuc)) va tich va ca viet~".
• Adding a wildcard symbol may retrieve word variants: su sach ((ty lang) OR (ty xang)) xa hoi. hieu van ((nam duc) or (nam thuc)) va tich va ca viet*.