Various tools and techniques are available to facilitate text and data mining tasks including APIs and specific TDM software. The choice of tool depends on the specific requirements of your TDM project, the programming language you are comfortable with, and the level of customisation and control you need over the analysis process.
Examples of tools you could use:
Crossref Text and Data Mining for Researchers
Designed to allow researchers to easily harvest full text documents from all participating publishers regardless of their business model (e.g. open access, subscription).
Digital Research Tools (DiRT) Directory
Aggregates information about digital research tools for scholarly use. DiRT makes it easy to find and compare resources available for text mining and data visualization (among others).
An open-source extension for Zotero, which is a program for creating bibliographies and building large text corpuses in an online database.
National Centre for Text Mining (NaCTeM) - Software
A few text mining software tools.
Resources and tools for computational research – MIT Libraries
A list of freely available APIs for text and data mining.