Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hieu van » hieu va, thien van, lieu va
van than » van thanh, van thang, van tuan
thai cua » than cua, tai cuc, tri cua
vai cua » dai cua, hai cua, lai cua
sach 2 » sach y
2 nang » v nang
luc va » tuc va, loc va
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 2 nang x hoi. hieu van than ((luc va) OR (duc va)) hanh ((vai cua) or (thai cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach 2 nang x hoi. hieu van than ((luc va) OR (duc va)) hanh ((vai cua) OR (thai cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach 2 nang x hoi. hieu van than ((luc va) OR (duc va)) hanh ((vai cua) or (thai cua)) tre".
• Adding a wildcard symbol may retrieve word variants: toc sach 2 nang x hoi. hieu van than ((luc va) OR (duc va)) hanh ((vai cua) or (thai cua)) tre*.