Scholarly monographs are useful when you need of more in-depth information on a broad topic, e.g. economy in European history. Oftentimes when doing family history research, you may not find a specific article on your ancestor's village or their specific occupation, but you may find some of this information buried in a monograph on a broader topic.

Start by looking specifically: czechoslovakia AND farming; peru AND weaving. This many bring you back results that have both of these words in the description. If this does not work, try to broaden your search. For example: Europe AND economy; Germany AND employment; China AND industrialization. These books may provide additional clues into the lives of your ancestors, but from a broader perspective. They can also provide a road map (references!) for additional sources.

This does not always work, but you might also try typing in a century, or a year, to see if anything appears, e.g. nineteenth-century.

To refine your results for books, under "Type" select Print Books and eBooks.

To find a scholarly monograph, make sure to look at the author (expert, researcher, professor) and the publisher (University or other academic press).