Keywords
Separate each keyword with “; “. For example: “Synthesis; HIV; Nucleoside Analogs; Boronic”. Use the Keywords field to store keywords that you want to associate with the reference. You can restrict a search to just the Keywords field in "Advanced Search", "Dynamic Folder", etc. Each keyword in this field is also entered into an index table so users can browse a lookup list of keywords and their associated references. This index table also helps users to enter keyword in a consistent way by suggesting existing keywords while you are typing.
Categories
Each category is also separated by "; ". Each category is surrounded by "_". For example: "_State Politics_; _Presidential Campaign_". Categories and keywords fields have similar forms. Keywords field is used to enter words and phrases about the reference. Categories field is used for tagging references in order to classify records, organize records by projects, etc.