Perhaps you should try some spelling variations:
thanh lap » thanh san, phan lap, thanh hai
toc sach » hoc sach, doc sach, thuoc sach
pham duy » pham duc
hieu van » hieu va, thien van, lieu va
van pham » san pham, van phan, van phat
nang ma » tang ma, sang ma, nang cao
sach ty » sach y, sach tu, sach thu
hanh va » hang va, hanh vi
xang ma » tang ma, sang ma, rang ma
cua tre » cua te, cuu tre, cua triet
duy va » duy vat, duy van, day 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 ty ((xang ma) or (nang ma)) hoi. hieu van pham duy va ((hanh va) or (thanh lap)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ty ((xang ma) OR (nang ma)) hoi. hieu van pham duy va ((hanh va) OR (thanh lap)) cua tre.
• Adding a wildcard symbol may retrieve word variants: toc sach ty ((xang ma) or (nang ma)) hoi. hieu van pham duy va ((hanh va) or (thanh lap)) cua tre*.