Google has reported that its core Internet business grew net revenue of 23 percent in the first quarter to $9.99 billion, as the company’s search advertising business continued to show strength. Google’s overall first quarter net income was $3.35 billion, or $9.94 per share, it said. That compares to net income of $2.89 billion, or $8.75 per share, in the same period last year. The company said, in a report Thursday, that it had consolidated revenue in the first quarter of $13.97 billion, versus $10.65 billion in the year-ago period. Google’s main Internet business generated $9.99 billion in first-quarter net revenue, which excludes fees paid to partner websites, compared to $8.14 billion in the first quarter of 2012.