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
vat hanh » van hanh, va hanh, nhat hanh
sach ky » sach y, sach ty, sach kem
cuu tre » cua tre, cau tren, cau treo
sac ky » cac ky, sai ky
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.

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