Perhaps you should try some spelling variations:
vat thanh » dat thanh, gat thanh, tat thanh
hieu van » hieu va, thien van, lieu va
nam thuc » nam thuoc, am thuc, nam thu
ban hang » ngan hang
te sach » toc sach
sach ky » sac ky, sach y, sach ty
cuu tre » cua tre, cau tren, cau treo
vi cuu » vi luu, vinh cuu
x hoi » xa hoi, o hoi, x ho

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

• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky nang x hoi. hieu van nam thuc ((vat thanh) OR (((ban hanh) OR (ban hang)))) vi cuu tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ky nang x hoi. hieu van nam thuc ((vat thanh) or (((ban hanh) OR (ban hang)))) vi cuu tre~".
• Adding a wildcard symbol may retrieve word variants: te sach ky nang x hoi. hieu van nam thuc ((vat thanh) or (((ban hanh) OR (ban hang)))) vi cuu tre*.