Perhaps you should try some spelling variations:
"spectral types with belligerents" » "special types with belligerents", "several types with belligerents", "special type with belligerents"
"neutral types with belligerents" » "neutral type with belligerents", "neuronal types with belligerents", "several types with belligerents"

Try widening your search to All Fields.

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

• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"neutral types with belligerents\") OR (\"spectral types with belligerents\"))".
• Removing quotes may allow a broader search: (( neutral types with belligerents ) OR ( spectral types with belligerents )).
• Adding a wildcard symbol may retrieve word variants: (("neutral types with belligerents") OR ("spectral types with belligerents"))*.