Apologies for the English, but I don't speak or read your language (Russian?). This answer is based on Google translate's version of what you asked.
PHP's super globals ($_GET
, $_POST
, etc.) are special variables, and it looks like you can't use these variables with PHP's variable variable feature. For example, this works
$foo = ['Hello'];
$var_name = 'foo';
var_dump($$var_name);
The "variable variable" $$var_name
expands as $'foo'/$foo
, and the variable dumps correctly.