A crucial step in the practice of evidence-based medicine is to locate the best available evidence regarding to clinical questions. In this article, we demonstrate that combining visualization techniques with traditional methods developed in evidence-based medicine could simplify the task. We describe a unifying framework for searching clinical evidence across multiple sources such as highly cited articles in the Web of Science and articles of particular types of study design in PubMed. We describe the implementation of a prototyping system to visualize the distribution of available evidence in a broader context of the underlying subject domain. We include examples of evidence found in the heart diseases and lung cancer literature. Practical implications on the design of visualization-based evidence searching tools are discussed.