Perhaps you should try some spelling variations:
"call options research : july 2009" » "call actions research : july 2009", "call optics research : july 2009", "call operations research : july 2009", "call option research : july 2009", "real options research : july 2009", "call options research : july 2008", "call options research : july 2007", "call options research : july 2019"
"scale options research : july 2012" » "scale actions research : july 2012", "scale optics research : july 2012", "scale operations research : july 2012", "share options research : july 2012", "care options research : july 2012", "case options research : july 2012", "scale options research : july 2013"

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: (("call options research : july 2009") OR ("scale options research : july 2012"))~.
• Removing quotes may allow a broader search: (( call options research : july 2009 ) or ( scale options research : july 2012 ))~.
• Adding a wildcard symbol may retrieve word variants: (("call options research : july 2009") or ("scale options research : july 2012"))*.