Perhaps you should try some spelling variations:
most economical » most economically, more economical, cost economics
gas economical » gas economic, _ economical, has economic
der recherche » de recherche, des recherches, en recherche
las economias » la economia, bias economics, gas economic
studie der » studien des, studie uber, studium der

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

• Performing a fuzzy search may retrieve terms with similar spellings: studie der recherche ((((las economias) OR (gas economical))) or (most economical)) aziendale ;~.
• If you are trying to use Boolean operators, they must be ALL CAPS: studie der recherche ((((las economias) OR (gas economical))) OR (most economical)) aziendale ;.
• The words AND, OR and NOT may confuse the search; try adding quotes: "studie der recherche ((((las economias) OR (gas economical))) or (most economical)) aziendale ;".
• Adding a wildcard symbol may retrieve word variants: studie der recherche ((((las economias) OR (gas economical))) or (most economical)) aziendale ;*.