GLOBAL MARKETS-Shares pull back after rally, dollar falls

* Global shares head for fourth week of gains * U.S. stock investors take profits after rally, tech results * Japan upper house election on Sunday in focus, yen up * Bonds, oil see quiet end to week; gold rises By Herbert Lash and Ryan Vlastelica NEW YORK, July 19 (Reuters) - Government debt prices rose and stock markets around the world retreated on Friday when disappointing results from Microsoft and Google gave investors pause after a recent string of gains that lifted m