Perhaps you should try some spelling variations:
cac nuoc » cap nuoc, dat nuoc, cua nuoc
van hanh » van thanh, ban hanh, van anh
hanh dai » hanh tai, hanh dao, vanh dai
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet

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

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