Which SEO technique is used by OpenCart Extensions?

Example:
Search Google for opencart one page checkout
https://www.google.com.br/search?q=open ... e+checkout

For me, the first three results point to three different contents (internal search / filter)

one PAGE checkout
http://www.opencart.com/index.php?route ... 20checkout

one STEP checkout
http://www.opencart.com/index.php?route ... 20checkout

SINGLE page checkout
http://www.opencart.com/index.php?route ... 20checkout

Is there a name for this technique ?

or

How to create a relationship between different terms (one page x one step x single page) AND return these different results to Google ?

Thank you

Marco