Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
hieu va » lieu va, hieu qua
dan dai » dat dai, can dai, dan dat
cua tre » cua te, cuu tre, cua triet
xuc va » tuc va, luc va, xac 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 ty nang x hoi. hieu va cac ((xuc va) or (duc va)) dan dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ty nang x hoi. hieu va cac ((xuc va) OR (duc va)) dan dai cua tre*.