help! where can i find practice tests for olympiads

<p>where can i find practice bio/physics/chem olympiad practice tests online? i'm planning on taking all of them this year, but i'm only takin AP BIo and AP PHysics so i'll prbably have to self-study chem.
i've tried googling but cant find any. maybe i'm just googling it wrong........
i know there are some out there. or maybe they're for sale, like the AMC problems. how do u suggest i prepare for them, like what textbooks should i use?
for bio i have the AP Campbell edition (i heard it's no different from the college campbell edition, is that right?)
for physics i have the halliday book
wht is the best book for chem?
thanks!!</p>

<p>i kno it seems silly to be taking all of them when im not really good at any subject right now -_-. but i want to so help please :)</p>

<p>Well, here's the 1997 physics olympiad test:
Details</a> for Physics Olympiad Exams
and you can buy the others by following a link from that page.</p>

<p>great thanks! what about any for bio and chem?</p>

<p>Google, USABO and USNCO.</p>

<p>i did. but there aren't a myriad of past tests, unlike the USAMO</p>