Perhaps you should try some spelling variations:
thanh dat » thanh san, thanh hai, thanh van
tat thanh » tai thanh, ta thanh, tat thang
toc sach » hoc sach, doc sach, thuoc sach
cam thuc » am thuc, cam thu, can thuc
nam thuc » nam thuoc, am thuc, nam thu
dat cua » dai cua, day cua, mat 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

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) OR (nam thuc)) tat thanh dat 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) OR (nam thuc)) tat thanh dat 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) OR (nam thuc)) tat thanh dat cua tre".
• Adding a wildcard symbol may retrieve word variants: toc sach y nang ((ma hoi) or (mai hoi)). hieu va ((cam thuc) OR (nam thuc)) tat thanh dat cua tre*.