Problem with Regular expression

Hi all. I have a problem: i want subs any characters from a string but i don't have fix the problem. The string that i want to manipulate is the value from a text field of a search engine. The characters that i want to try substitute is &&, &, +, -, |, ||, or, and, not in not case-sensitive mode with "". I have create a pattern like this: $str = "Sybase and PHP not ASP or JSP && Oracle not Andy | Perl || Python + Ruby"; $pattern = "/(\band\b)|(\bnot\b)|(\bor\b)|(\b&&\b)|(\b&\b)|(\b\.\b)|(\b\+\b)|(\b\|\|\b)|(\b\|\b)/i"; echo $str = preg_replace($pattern, "", $str, -1); But characters like + && don't subs with "". Thanks to all and sorry my bad language