Perhaps you should try some spelling variations:
toc sach » hoc sach, thuoc sach, nuoc sach
doc sach » hoc sach, nuoc sach, dac sac
hieu van » hieu va, thien van, hieu ve
hanh tai » thanh tai, hang tai, han tai
cam tuc » cam xuc, cam tu, nam thuc
va hanh » van hanh, va thanh, va danh
tai cua » thai cua, tai cuc, tri cua
tuc va » thuc va, truc va, tuc xa
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 (doc sach)) ky nang x hoi. ((hieu van) OR (lieu va)) cam tuc va hanh tai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (doc sach)) ky nang x hoi. ((hieu van) OR (lieu va)) cam tuc va hanh tai cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) or (doc sach)) ky nang x hoi. ((hieu van) OR (lieu va)) cam tuc va hanh tai cua te".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (doc sach)) ky nang x hoi. ((hieu van) OR (lieu va)) cam tuc va hanh tai cua te*.