My experience is that the search function on the Forum and to some extent on SOTT.net as well is not working really well - it's actually bad imho but I understand there are more important things to take care of so one needs to approach this as a quest, a learning process :). I use StartPage advanced search function, sometimes DuckDuckGo. Only when I know in more detail what to look for and where, I search in particular threads via the search button here.