Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
tham soc » cham soc, tham nuoc, thai son
van tham » van thanh, van tuan, van chat
hieu van » hieu va, thien van, lieu va
va hanh » van hanh, va thanh, va danh
vu sach » vu bach, su sach, vu khach
ly nang » ky nang, ly hang, ly quang
ly vang » ly hang, ly van, ly quang
soc va » hoc va, loc va, doc va
vi hoa » voi hoa, vi hoc, va hoa
x hoi » xa hoi, o hoi, x ho

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: ((toc sach) OR (vu sach)) ((ly nang) OR (ly vang)) x hoi. hieu van tham soc va hanh vi hoa viet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) or (vu sach)) ((ly nang) OR (ly vang)) x hoi. hieu van tham soc va hanh vi hoa viet~".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (vu sach)) ((ly nang) OR (ly vang)) x hoi. hieu van tham soc va hanh vi hoa viet*.