The WebElements online periodic table includes the bulk modulus of many of the elements in its section on periodicity (http://www.webelements.com/periodicity/bulk_modulus/). These data are derived from a number of older printed resources, including Samsonov's Handbook of the Physicochemical Properties of the Elements, which is located in the Chemistry Reference collection at QD466.A3413. The table in question, Mechanical Properties of the Elements: Modulus of Normal Elasticity, begins on p.387 and references the appropriate primary literature for each value.
The bulk modulus of a substance is defined as, "the ratio of compressive or tensile force applied to a substance per unit surface area to the change in volume of the substance per unit volume" (AccessScience, accessed October 25, 2012) It is also called the bulk modulus of elasticity, the compression modulus, the hydrostatic modulus, the modulus of compression, and the modulus of volume elasticity. Any of these names can be helpful in finding this property.
Since the Knovel Scientific and Engineering Online Reference Books are focused on all areas of engineering and other sciences, they contain a large number of mechanical properties, including bulk modulus. To locate these properties for a particular substance, you'll want to do a Data Search.
The CRC Handbook of Chemistry and Physics also has a table of Room Temperature Elastic Moduli and Mechanical Properties of the Rare Earth elements, which is located on page 4-119. The CRC Handbook is located in print in the Chemistry Library Reference collection and electronically. To navigate to this table in the electronic edition, click on the + sign beside Section 4 in the table of contents, select the link Physical Properties of the Rare Earth Elements, and scroll to the correct table.