$re = '/課長(?:補佐(?:代理(?:心得)?)?)?(?!心得|代理)/m';
$str = '課長、課長補佐、課長補佐代理、課長補佐代理心得
課長心得、課長代理 -- 部分マッチを排除できた
課長次第、課長志願 -- 妥当と思えるマッチ';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php