Perhaps you should try some spelling variations:
"human vector-5?-nucleotidase" » "human factor-5?-nucleotidase", "human ecto-5?-nucleotidase", "human effector-5?-nucleotidase"
"human vector-5?-nucleoside" » "human factor-5?-nucleoside", "human ecto-5?-nucleoside", "human effector-5?-nucleoside"
"human actor-5?-nucleotidase" » "human factor-5?-nucleotidase", "human actors-5?-nucleotidase", "human factors-5?-nucleotidase"

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: (((("human vector-5?-nucleotidase") OR ("human actor-5?-nucleotidase"))) OR ("human vector-5?-nucleoside")).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"human vector-5?-nucleotidase\") OR (\"human actor-5?-nucleotidase\"))) or (\"human vector-5?-nucleoside\"))".
• Removing quotes may allow a broader search: (((( human vector-5?-nucleotidase ) OR ( human actor-5?-nucleotidase ))) or ( human vector-5?-nucleoside )).
• Adding a wildcard symbol may retrieve word variants: (((("human vector-5?-nucleotidase") OR ("human actor-5?-nucleotidase"))) or ("human vector-5?-nucleoside"))*.