php正则匹配中文，英文字母，空格，去除特殊字符。

$wd='但要保留正常的某些VaGaaí′ú V2.';

$wd = mb_convert_encoding($wd, 'UTF-8', 'GB2312');\\只能对UTF8字符进行过滤。
preg_match_all('/[\s\x{4e00}-\x{9fff}a-zA-Z0-9#\[\]\{\}\'\"=+\-\(\)*&%$@]+/iu', $wd, $matches);
$wd = join('', $matches[0]);
$wd =  mb_convert_encoding($wd, "GB2312", "UTF-8");\\过滤后转换成GB2312
echo $wd