Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hieu cua » hieu qua, dieu cua, bieu cua
cau theo » cau thi, cau tao
nang xay » dang xay, nganh xay, nang xuan
xay hoi » xa hoi, tay hoi, cay phoi
hieu ca » hieu cac, hieu va, hieu xa
sach ky » sac ky, sach y, sach ty
dan vat » dang vat, van vat, dan va
cuu tre » cua tre, cau tren, cau treo
thu ca » thu cua, thu ha, thu ba
ca dan » cac dan, ca 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 ky nang xay hoi. ((hieu ca) OR (hieu cua)) nam thu ca dan vat ((cuu tre) or (cau theo))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky nang xay hoi. ((hieu ca) OR (hieu cua)) nam thu ca dan vat ((cuu tre) OR (cau theo)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ky nang xay hoi. ((hieu ca) OR (hieu cua)) nam thu ca dan vat ((cuu tre) or (cau theo))".
• Adding a wildcard symbol may retrieve word variants: toc sach ky nang xay hoi. ((hieu ca) OR (hieu cua)) nam thu ca dan vat ((cuu tre) or (cau theo))*.