Fijate si algo asi te sirve ... Saludos!!
Código PHP:
<?php
include("conex.php");
$pesa=$_POST['pesa'];
$marca=$_POST['marca'];
$model=$_POST['model'];
$tipus=$_POST['tipus'];
$color=$_POST['color'];
$ref=$_POST['ref'];
$posicio=$_POST['posicio'];
$estat=$_POST['estat'];
$preu=$_POST['preu'];
$query = mysql_query("SELECT * FROM 'productes' WHERE ".($pesa ? "pesa LIKE '".$pesa."'" : "")."
".($marca ? "marca LIKE '".$marca."'" : "")."
".($model ? "model LIKE '".$model."'" : "")."
".($tipus ? "tipus LIKE '".$tipus."'" : "")."
".($color ? "color LIKE '".$color."'" : "")."
".($ref ? "ref LIKE '".$ref."'" : "")."
".($posicio ? "posicio LIKE '".$posicio."'" : "")."
".($estat ? "estat LIKE '".$estat."'" : "")."
".($preu ? "preu LIKE '".$preu."'" : ""), $conn);
while ($resultado = mysql_fetch_array($query))
{
echo "Pesa ".$resultado['pesa']."<br />";
echo "Marca ".$resultado['marca']."<br />";
echo "Model ".$resultado['model']."<br />";
echo "Tipus ".$resultado['tipus']."<br />";
echo "Color ".$resultado['color']."<br />";
echo "Ref. ".$resultado['ref']."<br />";
echo "Posicio. ".$resultado['posicio']."<br />";
echo "Estat. ".$resultado['estat']."<br />";
echo "Preu. ".$resultado['preu']."<br />";
echo "<hr /><br />";
}
?>
<html>
<form enctype="multipart/form-data" name="form1" method="post" action="">
<table>
<tr><td>Pesa</td><td> <INPUT maxLength="100" size="25" name="pesa"></td></tr>
<tr><td>Marca</td><td> <INPUT maxLength="100" size="25" name="marca"></td></tr>
<tr><td>Model</td><td><INPUT maxLength="100" size="25" name="model"></td></tr>
<tr><td>Tipus</td><td><INPUT maxLength="100" size="25" name="tipus"></td>
<tr><td>Color</td><td><INPUT maxLength="100" size="25" name="color"></td>
<tr><td>Ref.</td><td><INPUT maxLength="100" size="25" name="ref"></td></tr>
<tr><td>Posicio</td><td><INPUT maxLength="100" size="25" name="posicio"></td></tr>
<tr><td>Estat</td><td><INPUT maxLength="100" size="25" name="estat"></td></tr>
<tr><td>Preu</td><td><INPUT maxLength="100" size="25" name="preu"></td></tr>
<tr><td><INPUT name="submit" type="submit" value="Buscar!"></td></tr></table></td></tr>
</table>
</form>
</html>