Perhaps you should try some spelling variations:
joint transportation » point transportation, coins transportation, joint transformation
going transportation » coins transportation, long transportation, point transportation
center discussion » century discussion, cancer discussion, centre discussion
research center » research chapter
paper » papers

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: "oecd/itf ((joint transportation) OR (going transportation)) research center discussion paper".
• Adding a wildcard symbol may retrieve word variants: oecd/itf ((joint transportation) OR (going transportation)) research center discussion paper*.