Perhaps you should try some spelling variations:
methane cycle » methane cycling (Expand Search), methionine cycle (Expand Search)
semino carlos » serrano carlos (Expand Search), bacino carlos (Expand Search), solano carlos (Expand Search)
cycle three » cycles three (Expand Search), chile three (Expand Search), cycle free (Expand Search)
carlos nora » carlos mora (Expand Search), carlos nara (Expand Search), carlos noa (Expand Search)
o methane » go methane (Expand Search), _ methane (Expand Search), a methane (Expand Search)
three non » three new (Expand Search)
m combs » m coombs (Expand Search), e combs (Expand Search), _ combs (Expand Search)
combs c » combs _ (Expand Search)
c net » c neto (Expand Search), _ net (Expand Search), u net (Expand Search)
nacl » natl (Expand Search), nac (Expand Search), nucl (Expand Search)

You can also try:

• Europeana
• Digital Public Library of America
• CORE

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( j m combs c net ) or ((( o methane cycle three non ) or ( 3.5 nacl semino carlos nora ))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( j m combs c net ) OR ((( o methane cycle three non ) OR ( 3.5 nacl semino carlos nora )))).
• Adding a wildcard symbol may retrieve word variants: (( j m combs c net ) or ((( o methane cycle three non ) or ( 3.5 nacl semino carlos nora ))))*.