Perhaps you should try some spelling variations:
cau treo » cau theo, cau tren, cau triet
sach ky » sac ky, sach ty, sach kem
thuc va » thuc vat, thuc dan, thuc day
dan tai » van tai, dan thi, han tai
tai cau » tai cac, tai cao
va nam » van nam, va nay
va dan » ca dan, va dao, va dau
x hoi » xa hoi, o hoi, x ho

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 ky) OR (sach y)) nang x hoi. hieu ((va nam) or (ha nam)) thuc va dan tai cau treo~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc ((sach ky) OR (sach y)) nang x hoi. hieu ((va nam) OR (ha nam)) thuc va dan tai cau treo.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc ((sach ky) OR (sach y)) nang x hoi. hieu ((va nam) or (ha nam)) thuc va dan tai cau treo".
• Adding a wildcard symbol may retrieve word variants: doc ((sach ky) OR (sach y)) nang x hoi. hieu ((va nam) or (ha nam)) thuc va dan tai cau treo*.