Perhaps you should try some spelling variations:
"slave trade / west indien, british" » "slave trade / west indies, british", "slave trade / west indian, british", "slave trade / west indians, british"
"slave trade / best indies, british" » "slave trade / west indies, british", "slave trade / east indies, british", "slave trade / west indie, british"

Try widening your search to All Fields.

You may be able to get more results by adjusting your search query.

• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"slave trade / best indies, british\") OR (\"slave trade / west indien, british\"))".
• Removing quotes may allow a broader search: (( slave trade / best indies, british ) OR ( slave trade / west indien, british )).
• Adding a wildcard symbol may retrieve word variants: (("slave trade / best indies, british") OR ("slave trade / west indien, british"))*.