We use a trading metaphor to study knowledge transfer in the sciences as well as the social sciences. The metaphor comprises
four dimensions: (a) Discipline Self-dependence, (b) Knowledge Exports/Imports, (c) Scientific Trading Dynamics, and (d) Scientific
Trading Impact. This framework is applied to a dataset of 221 Web of Science subject categories. We find that: (i) the Scientific
Trading Impact and Dynamics of materials science and transportation science have increased; (ii) biomedical disciplines, physics,
and mathematics are significant knowledge exporters, as is statistics and probability; (iii) in the social sciences, economics,
business, psychology, management, and sociology are important knowledge exporters; and (iv) Discipline Self-dependence is
associated with specialized domains which have ties to professional practice (e.g., law, ophthalmology, dentistry, oral surgery
and medicine, psychology, psychoanalysis, veterinary sciences, and nursing).