Perhaps you should try some spelling variations:
letter nervous » center nervous (Expand Search), lobster nervous (Expand Search), other nervous (Expand Search)
benign cause » benign course (Expand Search)
cause case » causes cases (Expand Search), cause cone (Expand Search), cause ca (Expand Search)
bj letter » bj letters (Expand Search), b.j letters (Expand Search), _ letter (Expand Search)
nervous c » nervous _ (Expand Search), nervous 5 (Expand Search), nervous a (Expand Search)
1 benign » _ benign (Expand Search), a benign (Expand Search), 2 benign (Expand Search)
case di » case did (Expand Search), case dti (Expand Search), case d (Expand Search)
case de » case due (Expand Search)
j beta » j beth (Expand Search)
c dis » c dias (Expand Search), c disc (Expand Search), c dos (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: (( bj letter nervous c dis ) OR ((( j beta nerve case di ) OR ( 1 benign cause case de ))))~.
• Adding a wildcard symbol may retrieve word variants: (( bj letter nervous c dis ) or ((( j beta nerve case di ) or ( 1 benign cause case de ))))*.