Perhaps you should try some spelling variations:
sprague studies » spruce studies, sprachen studien, suffrage studies
de filologia » di filologia, de filosofia, e fisiologia
filologia a » filologia e, filologica e, filosofia da
studies de » studies der, studies die, studies doe
rats » rate, rat

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: "(rats OR rays) sprague studies de filologia a literature".
• Adding a wildcard symbol may retrieve word variants: (rats OR rays) sprague studies de filologia a literature*.