Do dr. strauss's experiments prove that an operation can permanently improve intelligence?

Assuming this refers to Flowers for Algernon, no, they do not. At the end of the story, Charlie begins to see a recession in his intelligence. He reverts back to how he was at the beginning of the story. This proves that Dr. Strauss' experiments are not permanent.

To think how we can say those words, break them down, know their meaning and how to say them correctly.