Perhaps you should try some spelling variations:
dan khanh » dang khanh, van khanh, dat khanh
khanh dai » thanh dat, khanh van, phan dai
toc sach » hoc sach, doc sach, thuoc sach
hieu van » hieu va, thien van, lieu va
su sach » so sach, vu sach
ky lang » ky nang, ky dang, ky tang
lang xa » lang ha, dang xay, lang van
nam hoc » nam moc, nam hoi, am hoc
cua tre » cua te, cuu tre, cua triet

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: ((su sach) or (toc sach)) ky lang xa hoi. hieu van nam hoc dan khanh dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (toc sach)) ky lang xa hoi. hieu van nam hoc dan khanh dai cua tre.
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (toc sach)) ky lang xa hoi. hieu van nam hoc dan khanh dai cua tre*.