  The evolution of scientific fields has been attracting much attention in
recent years. One of the key issues in evolution of scientific field is to
quantify the dissimilarity between two collections of scientific publications
in literature. Many existing works study the evolution based on one or two
dissimilarity measures, despite the fact that there are many different
dissimilarity measures. Finding the appropriate dissimilarity measures among
such a collection of choices is of fundamental importance to the study of
scientific evolution. In this article, we develop a new measure of the
evolution combining twelve keyword-based temporal dissimilarities of the
scientific fields using the method of principal component analysis. To
demonstrate the usage of this new measure, we chose four scientific fields:
environmental studies, information science & library science, mechanical
informatics, and religion. A database consisting of 274453 bibliographic
records in these four chosen fields from 1991 to 2019 are built. The results
show that all these four scientific fields share an overall decreasing trend in
evolution from 1991 to 2019 and different fields exhibits different evolution
patterns during different time periods.
