You can upload searches coming from different databases to Rayyan as long as they're in an accepted "reference format" as explained in the upload page. It is important to keep in mind how references are laid out in the file exported by the database. It should be one of these:
See the sample files if in doubt.
Note that some databases may not export in any of these standard reference formats. In this case, you can try to open the file in a reference manager (e.g., Zotero or EndNote) and if it's able to read it then you can export the content of the file to one of the above formats. Another option, if the database can export to a CSV format, is to modify the file using MSExcel or GoogleSheet to make it compatible with the CSV format accepted by Rayyan.