Perhaps you should try some spelling variations:
toc sach » doc sach, thuoc sach, nuoc sach
hoc sach » hoc sinh, hoc cac, hoc anh
dam thuc » dan thuc, nam thuc, dai thuc
hieu va » lieu va, hieu qua
va hanh » van hanh, va thanh, va danh
v nang » va nang, vu nang, van nang
vi cua » vai cua, di cua
cua te » cua tu
x hoi » xa hoi, o hoi, x ho

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: ((toc sach) or (hoc sach)) v nang x hoi. hieu va ((dam thuc) or (am thuc)) va hanh vi cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (hoc sach)) v nang x hoi. hieu va ((dam thuc) OR (am thuc)) va hanh vi cua te.
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (hoc sach)) v nang x hoi. hieu va ((dam thuc) or (am thuc)) va hanh vi cua te*.