Perhaps you should try some spelling variations:
sach nuoc » sach duoc, cac nuoc, bach tuoc
hieu van » thien van, lieu va, hieu ve
danh doi » danh di, thanh doi, dung doi
so sach » bo sach, co sach, hoc sach
doi cua » dai cua, hoi cua
va danh » va dinh, va dan, va hanh
cua tre » cua te, cuu tre, cua triet
hieu va » lieu va, hieu qua
nang xa » nang x, lang xa, nang ma
so sanh » do sanh

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: ((so sach) or (so sanh)) ky nang xa hoi. ((hieu va) or (hieu van)) sach nuoc va danh doi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((so sach) OR (so sanh)) ky nang xa hoi. ((hieu va) OR (hieu van)) sach nuoc va danh doi cua tre.
• Adding a wildcard symbol may retrieve word variants: ((so sach) or (so sanh)) ky nang xa hoi. ((hieu va) or (hieu van)) sach nuoc va danh doi cua tre*.