Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
cau treo » cau theo, cau tren, cau triet
sach ky » sac ky, sach y, sach ty
thuc va » thuc vat, thuc dan, thuc day
dan vai » dan va, dan tai, den vai
dan vat » dang vat, van vat, dan va
va nam » van nam, va nay
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: toc sach ky nang x hoi. hieu ((va nam) or (ha nam)) thuc va ((dan vai) OR (dan vat)) cau treo~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky nang x hoi. hieu ((va nam) OR (ha nam)) thuc va ((dan vai) OR (dan vat)) cau treo.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ky nang x hoi. hieu ((va nam) or (ha nam)) thuc va ((dan vai) OR (dan vat)) cau treo".
• Adding a wildcard symbol may retrieve word variants: toc sach ky nang x hoi. hieu ((va nam) or (ha nam)) thuc va ((dan vai) OR (dan vat)) cau treo*.