Perhaps you should try some spelling variations:
thanh dai » thanh hai, thanh tai, thanh dat
toc sach » hoc sach, doc sach, thuoc sach
nang mai » nang ma, nang tai, lang mai
va thanh » gia thanh, ban thanh, va tinh
sach ly » sach y, sach lo, sach ty
ly nang » ky nang, ly hang, ly vang
mai hoi » mai khoi, dai hoi, lai hoi
hieu ve » hieu van
hieu va » lieu va, hieu qua
cac dac » cac dan, cac dai, cac bac
cua tre » cua te, cuu tre, cua triet
dac va » duc va, day va, dat va

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 ly nang mai hoi. ((hieu ve) or (hieu va)) cac dac va thanh dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ly nang mai hoi. ((hieu ve) OR (hieu va)) cac dac va thanh dai cua tre.
• Adding a wildcard symbol may retrieve word variants: toc sach ly nang mai hoi. ((hieu ve) or (hieu va)) cac dac va thanh dai cua tre*.