Perhaps you should try some spelling variations:
"mechanical engineering fisheries" » "electrical engineering fisheries", "mechanical engineering discoveries", "mechanical engineering properties", "mechanical engineering societies"
"mechanical engineering fields" » "electrical engineering fields", "mechanical bioengineering fields", "mechanical engineering fluid", "mechanical engineering food"
"mechanical engineering theories" » "electrical engineering theories", "mechanical engineering theory", "mechanical engineering theses", "mechanical engineering textiles"

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: (((("mechanical engineering fisheries") OR ("mechanical engineering fields"))) OR ("mechanical engineering theories")).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"mechanical engineering fisheries\") OR (\"mechanical engineering fields\"))) or (\"mechanical engineering theories\"))".
• Removing quotes may allow a broader search: (((( mechanical engineering fisheries ) OR ( mechanical engineering fields ))) or ( mechanical engineering theories )).
• Adding a wildcard symbol may retrieve word variants: (((("mechanical engineering fisheries") OR ("mechanical engineering fields"))) or ("mechanical engineering theories"))*.