Perhaps you should try some spelling variations:
doc sach » hoc sach, toc sach, nuoc sach
thuc dan » thuc hanh, hoc dan, thuc vat
dan danh » van danh, han danh, ban danh
van dam » van nam, van dao, van dau
sach ky » sac ky, sach y, sach ty
van am » van nam, van lam, van ai
vai va » mai va, dai va, lai va
hai va » hai van, thai va, hoi va
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 ((van am) or (van dam)) thuc dan danh ((vai va) or (hai va)) triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc sach ky nang x hoi. hieu ((van am) OR (van dam)) thuc dan danh ((vai va) OR (hai va)) triet.
• Adding a wildcard symbol may retrieve word variants: doc sach ky nang x hoi. hieu ((van am) or (van dam)) thuc dan danh ((vai va) or (hai va)) triet*.