Perhaps you should try some spelling variations:
doc sach » hoc sach, toc sach, nuoc sach
cau treo » cau theo, cau tren, cau triet
lang xa » dang xay, lang van
lang ha » long ha
sach ty » sach y, sach tu, sach thu
dan vai » dan va, dan tai, dan vat
vai cau » va cau, van cau, vai cac
hieu va » lieu va, hieu qua
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: doc sach ty ((lang xa) or (lang ha)) hoi. hieu va ((nam thu) or (am thuc)) ca dan vai cau treo~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc sach ty ((lang xa) OR (lang ha)) hoi. hieu va ((nam thu) OR (am thuc)) ca dan vai cau treo.
• Adding a wildcard symbol may retrieve word variants: doc sach ty ((lang xa) or (lang ha)) hoi. hieu va ((nam thu) or (am thuc)) ca dan vai cau treo*.