Exact search results

Hello there! I need some help with my code. I want that when I search for a code (for example CU17001) on the results page to see just the product which has in title that code. Right now, wuth the code I wrote, it shows 33 results such as: CU19001, CU17010, CU17006 etc.
Can someone help me please?
This is the code I use.