Perhaps you should try some spelling variations:
metal complex » metal complexes (Expand Search)
complex text » complete text (Expand Search), complex tear (Expand Search), complex team (Expand Search)
kuhl carlos » gual carlos (Expand Search), riehl carlos (Expand Search), diehl carlos (Expand Search)
carlos noa » carlos noe (Expand Search), carlos nodal (Expand Search), carlos nava (Expand Search)
comps con » compost con (Expand Search), comps los (Expand Search)
text ngoc » text nlo (Expand Search), text non (Expand Search), text now (Expand Search)
nacl kuhl » nacl kcl (Expand Search)
7.5 nacl » 3.5 nacl (Expand Search), 0.9 nacl (Expand Search)
con new » icon new (Expand Search), con nee (Expand Search), con net (Expand Search)
5 metal » 5 methyl (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 comps con new ) or ((( 5 metal complex text ngoc ) or ( 7.5 nacl kuhl carlos noa ))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( j m comps con new ) OR ((( 5 metal complex text ngoc ) OR ( 7.5 nacl kuhl carlos noa ))))*.