Perhaps you should try some spelling variations:
"quantum spectroscopy" » "momentum spectroscopy", "beam spectroscopy"
"quark spectroscopy" » "stark spectroscopy", "quasar spectroscopy", "dwarf spectroscopy"
"stars spectroscopy" » "stark spectroscopy", "stars spectroscopic", "state spectroscopy"

Try widening your search to All Fields.

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: (((("quark spectroscopy") OR ("quantum spectroscopy"))) OR ("stars spectroscopy")).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"quark spectroscopy\") OR (\"quantum spectroscopy\"))) or (\"stars spectroscopy\"))".
• Removing quotes may allow a broader search: (((( quark spectroscopy ) OR ( quantum spectroscopy ))) or ( stars spectroscopy )).
• Adding a wildcard symbol may retrieve word variants: (((("quark spectroscopy") OR ("quantum spectroscopy"))) or ("stars spectroscopy"))*.