Include theor* as one your search terms. It will find theory, theories, theoretical.
Many abstracts list the type of data collected so try using quanitative or qualitative as one your search terms.
Like this: women and social capital and quanitative
Most databases have a set of keywords that are used to associate keywords with articles focusing on those topics. They are usually called subjects, subject headings, or descriptors.
For example, when searching women and social capital in Sociological Abstracts you'll see the descriptors females and cultural capital. You can then do another search using those keywords to find more information on your topic.