Perhaps you should try some spelling variations:
specialist libraries » specialist librarians
spectral libraries » several libraries, spectral library
specific libraries » scientific libraries, specific injuries
special libraries » several libraries

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: academic & ((((specialist libraries) OR (spectral libraries))) OR (((specific libraries) OR (special libraries)))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "academic & ((((specialist libraries) or (spectral libraries))) or (((specific libraries) OR (special libraries))))".
• Adding a wildcard symbol may retrieve word variants: academic & ((((specialist libraries) or (spectral libraries))) or (((specific libraries) OR (special libraries))))*.