Results here are limited to books, ebooks, and book chapters.
The Library of Congress subject heading for systematic theology is Theology, Doctrinal. Using this you will find a much broader array of materials than searching solely for the phrase "systematic theology."
The Library of Congress section for Doctrinal Theology is BT. Subdivisions of this field are listed below:
BT 10-1480 Doctrinal Theology
Subject headings may begin with
CATHOLIC CHURCH - DOCTRINES OR THEOLOGY, DOCTRINAL
Either of the subject headings may be refined by adding
HISTORY - EARLY CHURCH
MIDDLE AGES
MODERN PERIOD
You can also narrow your search by adding a keyword like a person or theological cocnetp, (e.g., RAHNER) or (e.g. HOLY SPIRIT)
WorldCat: national catalog that you can use in comprehensive searches to identify books and other materials on your topic
A global catalog of library materials. You can search for books, music, video, articles, and more at libraries worldwide.