An Ethnography/Ethnology is a first-hand descriptive work of a particular culture or ethnic group based on the immersion and participation of the anthropologist in the culture and daily life of the people who are the subject of study.
This makes Ethnographies a particular type of research, because it is the record of an Anthropologists observations about a culture, its rituals, activities, structure and organization gained from direct participation in that culture's day-to-day life.
A history of the Maya is not an Ethnography. It tells the story of this people over the series of hundreds of years from an overarching perspective.
A record of Maya farming practices and rituals, recorded by someone who observed them while participating in their day-to-day life may be considered an Ethnography.
It is important to note that, while this guide provides access to lists of Ethnographies in the library catalog, these lists should not be considered to be complete or exhaustive. Furthermore, as there is no filter in the catalog that provides access to all Ethnographies, you will need to examine the text of any book you find in the catalog to see if it fits the criteria for an Ethnography.
This link takes you to the book review website Goodreads, where there is a list of popular ethnographic books. Using this list, you can select a book and then do a title search using the library catalog to see if the library has a copy.