There are over 16,000 NCDS variables in the nine full sweeps (plus the exams data). The task of finding the right ones for the research you want to undertake can be daunting.
The best way to start is to use the Online Data Dictionary, which is a searchable database containing a ‘record’ for every variable in all the main sweeps since birth. It is structured to reflect the data collection by subject within questionnaire / instrument and is also searchable using free text search.
The exact question wording corresponding to each variable is shown, and you can get frequency counts for each value.