What are the full text indexing capabilities of SharePoint 2013 Enterprise Search provides and how to enable Full Text Search. What are the file formats its supports?
1 Answer
Full text Indexing is explained in Technet article Overview of search result ranking in SharePoint Server 2013 as below.
A full-text index contains all the text from the searchable managed properties that are stored in that full-text index. Each full-text index is divided into weight groups, also referred to as contexts. The different contexts relate to the relative importance of a managed property, which is one of the ranking features that are used to calculate the total relevance rank. The number, or ID, of a context is not important; the ranking model determines its relative importance by assigning a contribution weight to a particular context. A higher contribution weight results in a higher ranking score.
Furthermore if you want to enable full text search, you will have to understand the search schema and Crawled properties and Managed Properties in the schema.
whenever an item gets crawled , Crawled property would be automatically created and that can be mapped to managed Property.
when mapped to Managed property,you can check whether that property need to be "full-text Index" or not by making the Managed property Searchable as shown in the picture and can assign appropriate Weight group by selecting the context.
All these are explained in that article overview of Search Schema
After that you can check on how to influence results.
with regards to the file types, I am not sure on that point on how it would be relevent , please explain your question to further assist.