I mentioned some of this in a thread yesterday, so I'll re-post that here.
We could change the forum search engine to give results on fewer characters searched for, but that would have two negative impacts. First, it would dramatically increase the search index size, and thus increase the database size and work load. Second, it would actually make many search results worse, since all the places that those letter combinations appeared inside another word would be returned results as well. For instance if the search engine were tweaked to let you search for 'UL', then it would also return result, pulk, bulk, SUL, pull, bull, full, etc... The more results returned, the less specific the results become.
So, it's a balance of several factors with the search string length. Where we're at isn't ideal. But it does work if you don't search for terms that are too generic (like underquilt).
Using Google to search the forum can be helpful sometimes. Their search algorithms are better than ours will ever be. And we should probably work on adding a Google search box to the site at some point, but there are some considerations with that as well.
We'll look into a Google Search box, but it will probably be a little while before it's fully implemented.
In the meantime, consider that searches for terms common enough to be abbreviations won't be very helpful anyway, since they are used so often. Try searching for the other criteria you're looking for (presumably there's something specific about an UQ or TQ that you want to find). And if you're just looking for the definitions of the abbreviations, check the list