Stocks shook off early weakness to post nice gains Wednesday, but volume was down. The Nasdaq notched the biggest gain of the major indexes, rising 1.1%. The S&P 500 and the NYSE rose 0.8% each. The Dow was the day's laggard, adding 0.5%. Volume fell 12% on the NYSE and 3% on the Nasdaq. Among industry groups, laggards took the lead role. Hospital and RV stocks jumped. Oil-related stocks were down, shadowing a drop in crude prices. The IBD 100