Why doesn't Google index some words on page?

Question

I've created a program in Delphi that uses Google's AJAX Search API to evaluate search phrase occurrences on specific sites, mine included. What surprised me was it doesn't appear Google is indexing some words on my pages, or I am forming my search queries via the API incorrectly. For example the search

site:www.delphi.org -"delphi programming" which uses the search string site%3Awww.delphi.org+-"delphi+programming" via the API

MarkDown doesn't like when I embed these links:

http://www.google.com/search?&q=site%3Awww.delphi.org+-"delphi+programming"

Clearly shows that all the pages returned have the phrase "Delphi programming" in the header or otherwise in the body text.

It is a different set then is returned by the search

site:www.delphi.org +"delphi programming" which uses the search string site%3Awww.delphi.org+%2B"delphi+programming" via the API

MarkDown doesn't like when I embed these links:

http://www.google.com/search?&q=site%3Awww.delphi.org+%2B"delphi+programming"

Maybe the issue is in WordPress. Is it looking at the pages differently? What am I missing?

Answer 1

Dunno about using the API, but if you do a plain google search with your 2 sentences, you'll get more hits (97) with [site:www.delphi.org +"delphi programming"] than with [site:www.delphi.org -"delphi programming"] which gets only 75.
The latter, using the - sign is supposed to return the hits without those words in context (according to Google Search Help). And it seems that in this case, it returns all the pages where "Delphi Programming" is not in the page (except in the header as it cannot avoid it). And also in the result pages, "Delphi programming" is not highlighted as a result. In the former search with the "+" sign, all occurrences of "Delphi programming" are displayed in bold in the results page.
So I guess [site:www.delphi.org -"delphi programming"] is kinda oxymoronic as a search...;-)