Perhaps you should try some spelling variations:
significantly observed » significantly altered (Expand Search), significantly clustered (Expand Search), significantly preferred (Expand Search)
significantly lower » significantly higher (Expand Search)
observed decrease » observed decreased (Expand Search)
lower decrease » linear decrease (Expand Search), larger decrease (Expand Search), teer decrease (Expand Search)

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

• Removing quotes may allow a broader search: (( significantly observed decrease ) OR ( significantly lower decrease ))*.