The words “obtain” and “attain” sound similar, but have different meanings.
The word “obtain” means “to get”. You can obtain physical things like reagents or non-physical things like results. Here’s an example:
These results were obtained by chromatin immunoprecipitation.
That means that the researchers used chromatin immunoprecipitation to get these results.
The word “attain” means “to achieve”. Here’s an example:
Our simulation study attained similar performance to that of the compared methods.
This means that their simulation achieved similar performance.
To review: You obtain something when you get or receive it. You attain something when you achieve it as an objective.