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