Perhaps you should try some spelling variations:
original conference » regional conference, retinal conference, regional conferences
einer original » eines originals, either original, ein original
year hormones » her hormones, yeasts hormones, fetal hormones

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: (( year hormones references ) OR ( einer original conference )).
• Adding a wildcard symbol may retrieve word variants: (( year hormones references ) or ( einer original conference ))*.