Perhaps you should try some spelling variations:
vat thanh » dat thanh, gat thanh, tat thanh
thanh doi » thanh loi, thanh moi, thanh do
toc sach » hoc sach, doc sach, thuoc sach
hieu van » hieu va, thien van, lieu va
nam thuc » nam thuoc, am thuc, nam thu
va triet » va thiet, va trien, ve triet
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
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: toc sach ky nang xa hoi. hieu van nam thuc vat thanh doi ((cua tre) or (va triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky nang xa hoi. hieu van nam thuc vat thanh doi ((cua tre) OR (va triet)).
• Adding a wildcard symbol may retrieve word variants: toc sach ky nang xa hoi. hieu van nam thuc vat thanh doi ((cua tre) or (va triet))*.