Adding filtering options

Additionally, the results list of co-occurring terms can be filtered by the following:

• Time of publication — define the search expression as follows: <term> and date[<|>|=]<year>
  e.g., "breast cancer" and date>2001

• Results containing the search term and any term in the selected dictionary which contains the entered term — define the search expression as follows: <term> and result:<term>
  e.g., "breast cancer" and result:pathway

• Topic map in which the results are grouped according to the last term (both singular and plural forms) in the phrase to organize the results according to topic — define the search expression as follows:
  <term> and result:topicmap