Searching is one of the "holy grail" topics in computing. There is always a lot of research being done on the subject, and I don't know of anything that approaches a "Unified Field Theory" for computer searching. There are several hotbeds of search research going on right now, each of which has specific features/benefits/restrictions.
What kind of material do you wish to search? This is probably the key question that you need to answer before you can start any real reading or learning. Searching pictures is very different from searching audio, and they are both very different than searching text. Each medium requires different tactics and radically different processes to search them.
Once you define your media, you need to decide what is important to be able to find as a result of your search. Macro searches deal with searching huge amounts of information with the goal of getting the searcher into the right vincinity and allowing the searcher to then refine their search. A macro search would be like specifying that you are interested in forrests or beaches on Google Earth, then allowing the search to find where you should look to refine your search criteria.
Micro searches usually follow the macro search, and they are designed to deal with far less data and to return very specific results. An example of this would be to feed a specific pattern of notes or lyrics to SoundHound and have it find that pattern within a given song or playlist. These searches are not possible on large amounts of data, but they can be just what is needed to get to a final answer in a search process.
Text seraches can be very different than "context aware" searches because there is only one context. Even though text can appear in multiple languages or dialects, the fundamental nature of text limits the amount of data and the ways that data can be organized. Text searching is very different than context aware searches, and requires a different mindset and different practices to achieve good results.
If you could offer some information about what kind(s) of data your website(s) will host, what you expect as search criteria, and what you want as a result of the search, then I could offer more specific suggestions on where you should look for more information.
-PatP