Perhaps you should try some spelling variations:
"mathematics and its applications, soviet theories" » "mathematics and its application, soviet theories", "mathematics and its applications, comet theories", "mathematics and its applications, secret theories"
"mathematics and its applications, soviet theory" » "mathematics and its application, soviet theory"
"mathematics and its applications, set theories" » "mathematics and its application, set theories", "mathematics and its applications, set theory"

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: (((("mathematics and its applications, soviet theories") OR ("mathematics and its applications, soviet theory"))) OR ("mathematics and its applications, set theories")).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"mathematics and its applications, soviet theories\") OR (\"mathematics and its applications, soviet theory\"))) or (\"mathematics and its applications, set theories\"))".
• Removing quotes may allow a broader search: (((( mathematics and its applications, soviet theories ) OR ( mathematics and its applications, soviet theory ))) or ( mathematics and its applications, set theories )).
• Adding a wildcard symbol may retrieve word variants: (((("mathematics and its applications, soviet theories") OR ("mathematics and its applications, soviet theory"))) or ("mathematics and its applications, set theories"))*.