Have you tried a parameter query? In the Access query design window, in the criteria line for the field, enter something like this:
[Please enter the value to search for:]
When the query is run, Access will bring up a text box where a user can enter a value. The limitation is that (I'm pretty sure) you cannot enter an expression like "Between 10 and 20". You can only enter values unless you use two of those prompts like this:
Between [Please enter low end of range] and [please enter upper end of range].