A lot of research means a significant amount or abundance of research that has been conducted on a particular topic. It implies that there is an extensive body of information available, gathered through thorough investigation and analysis.
I chose self publishing after doing lots of research on both forms. (authormarketingclub.com)
We did lots of research on different breeds and where we wanted to get one from. (janettaharvey.com)
I did lots of research before getting my french bulldog, and the reason certain colors were not allowed was particularly interesting to me. (thehappypuppysite.com)