Perhaps you should try some spelling variations:
complex task » complex than (Expand Search)
mll complex » small complex (Expand Search), cell complex (Expand Search), wall complex (Expand Search)
kuhl carlos » gual carlos (Expand Search), riehl carlos (Expand Search), diehl carlos (Expand Search)
carlos noel » carlos noe (Expand Search), carlos joel (Expand Search), carlos yoel (Expand Search)
campo con » campo como (Expand Search), campo c (Expand Search)
nacl kuhl » nacl kcl (Expand Search)
al campo » el campo (Expand Search), del campo (Expand Search), al cambio (Expand Search)
task ngo » task new (Expand Search), task age (Expand Search), task co (Expand Search)
con net » con nee (Expand Search), non net (Expand Search), upon net (Expand Search)
c mll » _ mll (Expand Search), c mel (Expand Search), c mpl (Expand Search)
j al » j a (Expand Search), j l (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 al campo con net ) or ((( c mll complex task ngo ) or ( 3.5 nacl kuhl carlos noel ))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( j al campo con net ) OR ((( c mll complex task ngo ) OR ( 3.5 nacl kuhl carlos noel )))).
• Adding a wildcard symbol may retrieve word variants: (( j al campo con net ) or ((( c mll complex task ngo ) or ( 3.5 nacl kuhl carlos noel ))))*.