Hi Tom, the search function is a bit iffy at the moment, we're currently working on sorting out the problems.
It should work out like this when it is working properly:
hammer drill Find posts that contain at least one of these words.
"hammer drill" Find posts that contain the exact phrase "hammer drill" e.g. "battery hammer drill", but not "hammer and drill".
+battery +drill Find posts that contain both words.
+drill hammer Find posts that contain the word "drill", but rank it higher if it also contains "hammer".
+drill -hammer Find posts that contain the word "drill" but not "hammer".
+drill +(>percussion <impact) Find posts that contain "drill'' and "percussion", or "drill" and "impact" (in any order), but rank "percussion drill" higher than "impact drill".
screw* Find posts that start with the word "screw" e.g. "screw", "screws", "screwdriver" and "screwdigger".