Perhaps you should try some spelling variations:
tat thanh » tai thanh, ta thanh, tat thang
vat thanh » dat thanh, gat thanh, viet thanh
toc sach » hoc sach, doc sach, thuoc sach
cam thuc » am thuc, nam thuc, cam thu
van cua » vang cua, ban cua, dan cua
cua tre » cua te, cuu tre, cua triet
hieu va » lieu va, hieu qua
mai hoi » mai khoi, dai hoi, lai hoi
y nang » ky nang, ly nang, v nang
ma hoi » xa hoi, ma hoa, me hoi
va cam » va cham, va cac, va cao

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 y nang ((ma hoi) or (mai hoi)). hieu va cam thuc ((vat thanh) OR (tat thanh)) van cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach y nang ((ma hoi) OR (mai hoi)). hieu va cam thuc ((vat thanh) OR (tat thanh)) van cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach y nang ((ma hoi) or (mai hoi)). hieu va cam thuc ((vat thanh) OR (tat thanh)) van cua tre".
• Adding a wildcard symbol may retrieve word variants: toc sach y nang ((ma hoi) or (mai hoi)). hieu va cam thuc ((vat thanh) OR (tat thanh)) van cua tre*.