Tools That You Can Use in Writing

In the past, I use thesaurus dictionaries in writing, but nowadays I tend to use corpus which contains the function of web concordancer to find right words. Here are the tools you may try.
http://www.americancorpus.org/x.asp?L=e&co=anc&c=olbalbpjo&e=yuying@mail.ntust.edu.tw http://www.edict.com.hk/vlc/
http://www.natcorp.ox.ac.uk/
http://llrc.eng.ntnu.edu.tw/English/search/