Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
toc sach » hoc sach, doc sach, nuoc sach
dang xay » dang van, van xay
ky dang » ky nang, ky danh
xay hoi » xa hoi, tay hoi, cay phoi
thuc va » thuc vat, thuc dan, thuc day
dau vai » dau va, dau hai, dau tai
vai cuu » vai cua
cuu tre » cua tre, cau tren, cau treo
va nam » ha nam, va nay
va dau » va dao

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) OR (thuoc sach)) ky dang xay hoi. hieu ((va nam) or (van nam)) thuc va dau vai cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (thuoc sach)) ky dang xay hoi. hieu ((va nam) OR (van nam)) thuc va dau vai cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) OR (thuoc sach)) ky dang xay hoi. hieu ((va nam) or (van nam)) thuc va dau vai cuu tre".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) OR (thuoc sach)) ky dang xay hoi. hieu ((va nam) or (van nam)) thuc va dau vai cuu tre*.