When searching in this database you have three different ways of making the search.
Exact ~ e.g. in last name write "montgomery of alamein". Do not just write "montgomery". Although you will find some generals named montgomery but not Monty.
Partial ~ e.g. in last name write "montgo". This will find Monty, but also Montogomery-Massingberd.
Similar ~ Unsure of the spelling. Is it Zhukov or Shukov then try to use similar.
Remember that you can combine the different fields, e.g. it is always a good idea to choose, which nation you are interested in.