Perhaps you should try some spelling variations:
toc sach » doc sach, thuoc sach, nuoc sach
hoc sach » hoc sinh, hoc cac, hoc anh
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
nuoc gia » nuoc giai, nuoc giao, quoc gia
thanh di » thanh doi, thanh de, thanh do
vu nang » vuc nang, va nang, vu dang
hieu va » lieu va, hieu qua
cua tre » cuu tre, cua triet, dua tren
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)) vu nang x hoi. hieu va cac nuoc gia thanh di ((cua tre) OR (cua te))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (hoc sach)) vu nang x hoi. hieu va cac nuoc gia thanh di ((cua tre) OR (cua te)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) or (hoc sach)) vu nang x hoi. hieu va cac nuoc gia thanh di ((cua tre) OR (cua te))".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (hoc sach)) vu nang x hoi. hieu va cac nuoc gia thanh di ((cua tre) OR (cua te))*.