Give the number of papers that were published on "IEEE Transactions on Nuclear Science" in 1999.
'IEEE Transactions on Nuclear Science' is the FullName of journal; 1999 refers to Year = '1999'; papers refers to Paper.Id
SELECT COUNT(T2.Id) FROM Journal AS T1 INNER JOIN Paper AS T2 ON T1.Id = T2.JournalId WHERE T1.FullName = 'IEEE Transactions on Nuclear Science' AND T2.Year = 1999
database name:db_id authors
Author table Author Cols: Id dtype integer, Name dtype text, Affiliation dtype text, 
Conference table Conference Cols: Id dtype integer, ShortName dtype text, FullName dtype text, HomePage dtype text, 
Journal table Journal Cols: Id dtype integer, ShortName dtype text, FullName dtype text, HomePage dtype text, 
Paper table Paper Cols: Id dtype integer, Title dtype text, Year dtype integer, ConferenceId dtype integer, JournalId dtype integer, Keyword dtype text, 
PaperAuthor table PaperAuthor Cols: PaperId dtype integer, AuthorId dtype integer, Name dtype text, Affiliation dtype text, 
