Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
thi hang » thi hanh, thi nang, thi hong
cam thuc » nam thuc, cam thu, can thuc
vat danh » va danh, van danh, luat danh
danh hai » dang hai, lanh hai, manh hai
ty hang » ly hang, ty xang, thu hang
hai cua » thai cua, dai cua, hoi cua
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 ((ty hang) OR (thi hang)) xa hoi. lieu va ((cam thuc) or (am thuc)) vat danh hai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ((ty hang) OR (thi hang)) xa hoi. lieu va ((cam thuc) OR (am thuc)) vat danh hai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ((ty hang) OR (thi hang)) xa hoi. lieu va ((cam thuc) or (am thuc)) vat danh hai cua tre".
• Adding a wildcard symbol may retrieve word variants: toc sach ((ty hang) OR (thi hang)) xa hoi. lieu va ((cam thuc) or (am thuc)) vat danh hai cua tre*.