i cannot find information about the terms "this" and "new" theyr names are too general

while using uniscite ive come across the terms "new" and "this" and since they seem to be pretty usefull statements i want to lear about theyr proper usage but theyr names are too generals so searchs come up with nothing and i cannot find enteries about them in the reference manual , would someone care to enlighten me ?

http://msdn.microsoft.com/en-us/library/x53a06bb(v=vs.80).aspx