Comment 1 for bug 1027349

those two queries are not the same because in the first one, you didnt encode the "plus" in the url so the browser will understand it as a concatenation : %D9%8A%D9%88%D8%B3%D9%81%20 + %20%D9%85%D8%B5%D8%B1 مصر يوسف

in the second query, the "plus" is encoded to "%2B"

That's the right writing to search for "مصر + يوسف" ,

try always to encode the special characters in the url