Strong earnings reports pushed the Dow Jones industrial average back into record territory Wednesday. The Dow ended the day up 50.57 points, closing at 5,242.84. The New York Stock Exchange composite index also rose today, gaining 3.19 to finish the day at 331.72. On the Big Board, advancers led decliners 1,483 to 900, with 725 unchanged. Volume was heavy, with 475.89 million shares traded. The technology-heavy Nasdaq composite index gained 15.42 to close at 1,043.46. The Standard & Poor's 500 stocks rose 7.17 to finish at 619.96. The American Stock Exchange market value index rose 3.95 to 537.51. In London, gold closed at $403.25, down $0.40.