Perhaps you should try some spelling variations:
1720 early » 1727 early, 1820 early, 1770 early
2 fission » _ fission, a fission, 3 fission
2f early » 24 early, 23 early, 25 early
21 early » 2.1 early, 11 early, 1.1 early
22 early » 2 early, 12 early, 1722 early
20 early » 10 early, 1820 early

Try widening your search to All Fields.

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: %22ethiopia %2 fission %((((((2f early) OR (((21 early) OR (1 early))))) OR (22 early))) OR (((20 early) OR (1720 early)))) works to 1800%22.
• Adding a wildcard symbol may retrieve word variants: %22ethiopia %2 fission %((((((2f early) or (((21 early) or (1 early))))) or (22 early))) or (((20 early) or (1720 early)))) works to 1800%22*.