Perhaps you should try some spelling variations:
mengual reserve » medical reserve (Expand Search), legal reserve (Expand Search), renal reserve (Expand Search)
reserve system » research system (Expand Search), nerve system (Expand Search), research systems (Expand Search)
observer van » observer gain (Expand Search), observer hand (Expand Search), observer a (Expand Search)
cent nerve » bent nerve (Expand Search), recent nerve (Expand Search), crest nerve (Expand Search)
j mengual » j amengual (Expand Search), m mengual (Expand Search), e mengual (Expand Search)
system de » system der (Expand Search), system delay (Expand Search)
van dis » van die (Expand Search), van diest (Expand Search), van dijk (Expand Search)
nerve c » nerve cn (Expand Search), nerve co (Expand Search), nerve ct (Expand Search)
i cent » i cento (Expand Search), ai cent (Expand Search), ii cent (Expand Search)
c disc » c disch (Expand Search), isc disc (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: (((( 3 inter observer van dis ) or ( i cent nerve c disc ))) or ( j mengual reserve system de ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((( 3 inter observer van dis ) OR ( i cent nerve c disc ))) OR ( j mengual reserve system de )).
• Adding a wildcard symbol may retrieve word variants: (((( 3 inter observer van dis ) or ( i cent nerve c disc ))) or ( j mengual reserve system de ))*.