Is it possible to obtain a dataset of all search results in a google maps search? For example: if I want a list of all gas stations in Chicago, complete with addresses, store name, latitude-longitude coordinates etc.
Is such a data set against Google user agreement terms? I only plan on using the data for academic research questions.
Yes, it is possible, using the Google Places API.
Just for completeness sake: This is most definitely not open data. For an open alternative, have a look at Phil's answer about Open Street Maps.
If your usage complies with Google's terms depends on what exactly you plan to do with the data. I guess section 10.1.3 of the Google Maps/Google Earth APIs Terms of Service will be most relevant for you:
(a) No Unauthorized Copying, Modification, Creation of Derivative Works, or Display of the Content. You must not copy, translate, modify, or create a derivative work (including creating or contributing to a database) of, or publicly display any Content or any part thereof except as explicitly permitted under these Terms. For example, the following are prohibited: (i) creating server-side modification of map tiles; (ii) stitching multiple static map images together to display a map that is larger than permitted in the Maps APIs Documentation; (iii) creating mailing lists or telemarketing lists based on the Content; or (iv) exporting, writing, or saving the Content to a third party's location-based platform or service.
(b) No Pre-Fetching, Caching, or Storage of Content. You must not pre-fetch, cache, or store any Content, except that you may store: (i) limited amounts of Content for the purpose of improving the performance of your Maps API Implementation if you do so temporarily (and in no event for more than 30 calendar days), securely, and in a manner that does not permit use of the Content outside of the Service; and (ii) any content identifier or key that the Maps APIs Documentation specifically permits you to store. For example, you must not use the Content to create an independent database of "places" or other local listings information.
(c) No Mass Downloads or Bulk Feeds of Content. You must not use the Service in a manner that gives you or any other person access to mass downloads or bulk feeds of any Content, including but not limited to numerical latitude or longitude coordinates, imagery, visible map data, or places data (including business listings). For example, you are not permitted to offer a batch geocoding service that uses Content contained in the Maps API(s).
For licensing and ease-of-use purposes, you are better going with Open Street Maps. See, for example, these answers about how to use the data.
You can download all the OSM data (instructions) or use one of the several public APIs or prepacked databases (details). Mapquest is one API provider using OSM data and with very generous free request quotas.
