Find Whole Word Only in Acrobat Standard 2017

Our office recently updated to Acrobat Standard 2017. In previous versions, I would frequently use the CTRL+F Find command. When I try this in the 2017 version, it is very limited. I am unable to select an option for "whole word only". The outcome is that when I search for a word like "rain" in a document, I am shown results such as "drainage" "grains" and "unrestrained". If I try to search with the word "rain" in quotes like this, I get no results. Has this incredibly useful tool been moved somewhere else, not to be seen by simply using CTRL+F? Thanks in advance for your help!