Perhaps you should try some spelling variations:
complex concepts » complex confers (Expand Search), complex controls (Expand Search), complex concentrates (Expand Search)
carlos negras » carlos negrao (Expand Search), carlos ferras (Expand Search), carlos negro (Expand Search)
hard complex » card complex (Expand Search), hand complex (Expand Search), hrd complex (Expand Search)
bauer carlos » bauer charles (Expand Search), bauer carl (Expand Search), bauer carol (Expand Search)
comps icon » comps con (Expand Search)
concepts a » concepts _ (Expand Search)
nacl bauer » nacl based (Expand Search)
icon new » bacon new (Expand Search), icon fes (Expand Search), icon lem (Expand Search)
7.5 nacl » 3.5 nacl (Expand Search), 0.9 nacl (Expand Search)
l comps » m comps (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.

• If you are trying to use Boolean operators, they must be ALL CAPS: (( j l comps icon new ) OR ((( a hard complex concepts a ) OR ( 7.5 nacl bauer carlos negras ))))~.
• Adding a wildcard symbol may retrieve word variants: (( j l comps icon new ) or ((( a hard complex concepts a ) or ( 7.5 nacl bauer carlos negras ))))*.