You can get them on ncert.nic.in (the official website of NCERT)
it is a difficult exam and you can refer the site below for sample papers , free online books for download etc.
NTSE previous year paper and sample paper available on Aryan Classes website.
it is quite difficult to get UP previous exam paper but you can get other papers on website Aryanclasses.com, on this website almost all ntse previous papers are available.
you can find it at aryan classes
1995
icmr jrf sample papers
from which website i can get the sample papers of CAPITAL IQ
You can get the best CBSE sample papers on the Internet at cbseguess.com.
f7
KnowledgeBin.org provides VITEEE 2009 sample question papers.. VITEEE 2009 Sample Question Papers - Mathematics VITEEE 2009 Sample Question Papers - Chemistry VITEEE 2009 Sample Question Papers - Physics http://knowledgebin.org/kb/Other_Exams_17/
CBSE Sample Papers are available on various websites. Download them free and slove them.
http://cce.icbse.com/cce-sample-papers/