Perhaps you should try some spelling variations:
"quark spectroscopy" » "quasar spectroscopy", "cars spectroscopy", "quantum spectroscopy"
"stark spectroscopy" » "state spectroscopy", "cars spectroscopy", "contact spectroscopy"
"stars spectroscopy" » "stars spectroscopic", "state spectroscopy", "cars 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 ("stark spectroscopy"))) OR ("stars spectroscopy")).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"quark spectroscopy\") OR (\"stark spectroscopy\"))) or (\"stars spectroscopy\"))".
• Removing quotes may allow a broader search: (((( quark spectroscopy ) OR ( stark spectroscopy ))) or ( stars spectroscopy )).
• Adding a wildcard symbol may retrieve word variants: (((("quark spectroscopy") OR ("stark spectroscopy"))) or ("stars spectroscopy"))*.