two issues I noticed in get-alias

I found two issues with get-alias. Maybe I’m doing something wrong. First one is that the alias of cmdlets are not found.
If I type get-alias ls, the appropriate cmdlet is printed out. If I type get-alias get-children, I get zippo.
I tried filtering the results of get-alias with where-object, but I weirdly doesn’t work.

gal | out-string |? Name -like "Set-Alias"

outputs nothing, but

gal | out-string |? Name -like "sal"

works and print out

Alias sal -> Set-Alias