Use commas to separate words and phrases, e.g. "plesiosaur, cervical vertebra, pliensbachian". You can search in one or more fields, and for all or any of the words or phrases.
'Raw Text' refers to a dump of the whole text in a pdf pasted into the database as plain text.

For the year, there are options on how to search:
Just the year (e.g. '2000') will list results for the year only
Years separated by commas (e.g 2000,2010) lists results for all the years listed
Use the '>' and '<' symbols for before or after the year (e.g. '> 2000' lists all papers published after that year)
'Between ... and ' (e.g. between 2000 and 2010) lists papers published in that time frame
If you leave this field blank it will list all papers regardless of year